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                                                                       EXHIBIT 9




                            STOCK PURCHASE AGREEMENT

                          DATED AS OF FEBRUARY 7, 2001

                                 BY AND BETWEEN

                       CHICAGO BRIDGE & IRON COMPANY N.V.

                                       AND

                                 FARINVEST, LTD.

       IN CONNECTION WITH THE FUNDING OF THE PURCHASE OF CERTAIN ASSETS OF

                              PITT-DES MOINES, INC.

                                       BY

                       CHICAGO BRIDGE & IRON COMPANY N.V.









================================================================================


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                               PURCHASE AGREEMENT


                  THIS STOCK PURCHASE AGREEMENT (this "Agreement") is made and
entered into as of February 7, 2001 by and between Chicago Bridge & Iron Company
N.V., a Netherlands company ("CB&I") and Farinvest, Ltd. ("WEDGE"), a Cayman
Islands company, and relating to the funding of the purchase by CB&I of certain
divisions of Pitt-Des Moines, Inc. ("PDM"), a Pennsylvania corporation.

                                  INTRODUCTION

                  WHEREAS, PDM, CB&I and CB&I Constructors, Inc., a Texas
corporation ("CB&I Sub"), are simultaneously entering into that certain Asset
Purchase Agreement of even date herewith (the "Asset Purchase Agreement")
pursuant to which CB&I and CB&I Sub are purchasing certain assets of PDM (the
"PDM Acquisition");

                  WHEREAS, CB&I wishes to sell to WEDGE, and WEDGE wishes to
purchase from CB&I, 837,692 shares of common stock, par value NLG .01 per share,
of CB&I (the "PDM Financing Shares"); and

                  WHEREAS, CB&I intends to use the funds from the sale to WEDGE
of the PDM Financing Shares to finance a portion of the PDM Acquisition.

                  NOW, THEREFORE, in consideration of the premises and the
representations, warranties, covenants and agreements stated herein, and upon
the terms and subject to the conditions hereinafter set forth, the parties
hereto hereby agree as follows:

                                   ARTICLE I

                                   DEFINITIONS


          Section 1.01 Definitions. As used herein, the following terms shall
have the meanings set forth below:

                  "Affiliate" means, as to any specified Person, any other
Person that, directly or indirectly through one or more intermediaries or
otherwise, controls, is controlled by or is under common control with the
specified Person. As used in this definition, "control" means the possession,
directly or indirectly, of the power to direct or cause the direction of the
management or policies of a Person (whether through ownership of Capital Stock
of that Person, by contract or otherwise).

                  "Agreement" means this Agreement, including all attached
Schedules, Annexes, Addenda and Exhibits, as the same may be amended, modified
or supplemented from time to time.

                  "Alternative Proposal" means any unsolicited proposal with
respect to any alternative financing transaction.


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                  "Amendment to the Shareholder Agreement" means the amendment
to the Shareholder Agreement dated as of even date herewith in the form attached
hereto as Exhibit A.

                  "Asset Purchase Agreement" has the meaning specified in the
Introduction.

                  "Business Combination" means a merger, combination or
consolidation (whether or not CB&I or a Subsidiary of CB&I is the surviving
entity in such transaction), tender offer or share exchange (whether for all or
part of the outstanding Securities of CB&I or any Subsidiary), business
combination, sale of significant assets, dissolution, liquidation or similar
transaction involving CB&I or any Subsidiary or division of CB&I.

                  "Capital Stock" means, with respect to: (a) any corporation,
any share, or any depositary receipt or other certificate representing any
share, of an equity ownership interest in that corporation; and (b) any other
Entity, any share, membership or other percentage interest, unit of
participation or other equivalent (however designated) of an equity interest in
that Entity.

                  "CB&I" has the meaning specified in the first paragraph of
this Agreement.

                  "CB&I Sub" has the meaning specified in the first paragraph of
this Agreement.

                  "CB&I Stock" means the common stock of CB&I, par value NLG .01
per share.

                  "CERCLA" means the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, as amended, (42 U.S.C. sections 9601 et
seq.).

                  "Charter Documents" means, with respect to any Entity at any
time, in each case as amended, modified and supplemented at that time, (a) the
articles or certificate of formation, incorporation, association or organization
(or the equivalent organizational documents) of that Entity, (b) the bylaws,
limited liability company agreement or regulations, or partnership agreements
(or the equivalent governing documents) of that Entity, and (c) each document
setting forth the designation, amount and relative rights, limitations and
preferences of any class or series of that Entity's Capital Stock or of any
rights in respect of that Entity's Capital Stock.

                  "Closing" has the meaning specified in Section 3.03.

                  "Closing Date" has the meaning specified in Section 3.03.

                  "Code" means the Internal Revenue Code of 1986, as amended,
reformed or otherwise modified from time to time.

                  "Commission" means the Securities and Exchange Commission of
the United States.

                  "Confidential Information" means, with respect to any Person,
all trade secrets and other confidential, nonpublic and/or proprietary
information of that Person, including information derived from reports,
investigations, research, work in progress, codes, marketing and sales programs,
capital expenditure projects, cost summaries, pricing formulae, contract
analyses, financial information, projections, confidential filings with any
Governmental



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Authority and all other confidential, nonpublic concepts, methods of doing
business, ideas, materials or information prepared or performed for, by or on
behalf of that Person.

                  "Damage" to any specified Person means any cost, damage
(including any consequential, exemplary, punitive or treble damage) or expense
(including reasonable fees of, and actual disbursements by, attorneys,
consultants, experts or other Representatives and Litigation costs) to, any fine
of or penalty on, or any liability (including loss of earnings or profits) of
any other nature of that Person.

                  "Effective Time" has the meaning specified in Section 3.02.

                  "Entity" means any sole proprietorship, corporation,
partnership of any kind having a separate legal status, limited liability
company, business trust, unincorporated organization or association, mutual
company, joint stock company or joint venture.

                  "Environmental Laws" means any and all Governmental
Requirements, common law rule (including but not limited to the common law
respecting nuisance and tortuous liability), or other requirement having the
force and effect of law, relating to the environment, including ambient air,
surface water, land surface or subsurface strata, or to emissions, discharges,
releases or threatened releases of pollutants, contaminants, chemicals or
industrial, toxic or hazardous substances or wastes (including Solid Wastes,
Hazardous Wastes or Hazardous Substances) or noxious noise or odor into the
environment, or otherwise relating to the manufacture, processing, distribution,
use, treatment, storage, disposal, recycling, removal, transport or handling of
pollutants, contaminants, chemicals or industrial, toxic or hazardous substances
or wastes (including petroleum, petroleum distillates, asbestos or
asbestos-containing material, polychlorinated biphenyls, chlorofluorocarbons
(including chlorofluorocarbon-12) or hydrochloro-fluorocarbons).

                  "ERISA" means the Employee Retirement Income Security Act of
1974, as amended.

                  "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

                  "Funding Agreement" means the Standby Funding Agreement among
WEDGE, PDM and CB&I attached hereto as Exhibit D.

                  "GAAP" means generally accepted accounting principles and
practices in the United States as in effect from time to time, which have been
or are applied on a basis consistent with past practice.

                  "Governmental Approval" means at any time any authorization,
consent, approval, permit, franchise, certificate, license, implementing order
or exemption of, or registration or filing with, any Governmental Authority,
including any certification or licensing of a natural person to engage in a
profession or trade or a specific regulated activity, at that time.

                  "Governmental Authority" means (a) any national, state,
county, municipal or other government, domestic or foreign, or any agency,
board, bureau, commission, court, department or other instrumentality of any
such government, or (b) any Person having the



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authority under any applicable Governmental Requirement to assess and collect
Taxes for its own account.

                  "Governmental Requirement" means at any time (a) any law,
statute, code, ordinance, order, rule, regulation, judgment, decree, injunction,
writ, edict, award, or authorization of any Governmental Authority in effect at
that time or (b) any obligation included in any certificate, certification,
franchise, permit or license issued by any Governmental Authority or resulting
from binding arbitration, including any requirement under common law, at that
time.

                  "Guaranty" means, for any specified Person, without
duplication, any liability, contingent or otherwise, of that Person guaranteeing
or otherwise becoming liable for any obligation of any other Person (the
"primary obligor") in any manner, whether directly or indirectly, and including
any liability of the specified Person, direct or indirect, (a) to purchase or
pay (or advance or supply funds for the purchase or payment of) that obligation
or to purchase (or to advance or supply funds for the purchase of) any security
for the payment of that obligation, (b) to purchase property, securities or
services for the purpose of assuring the owner of that obligation of its payment
or (c) to maintain working capital, equity capital or other financial statement
condition or liquidity of the primary obligor so as to enable the primary
obligor to pay that obligation; provided, that the term "Guaranty" does not
include endorsements for collection or deposit in the ordinary course of the
endorser's business.

                  "HSR Act" means the Hart-Scott-Rodino Antitrust Improvements
Act of 1976, as amended from time to time.

                  "Indebtedness" of any Person means, without duplication, (a)
any liability of that Person (i) for borrowed money or arising out of any
extension of credit to or for the account of that Person (including
reimbursement or payment obligations with respect to surety bonds, letters of
credit, banker's acceptances and similar instruments), for the deferred purchase
price of property or services or arising under conditional sale or other title
retention agreements, other than trade payables arising in the ordinary course
of business, (ii) evidenced by notes, bonds, debentures or similar instruments,
(iii) in respect of capital leases or (iv) in respect of interest rate
protection agreements, (b) any liability secured by any Lien upon any property
or assets of that Person (or upon any revenues, income or profits of that Person
therefrom), whether or not that Person has assumed that liability or otherwise
become liable for the payment thereof or (c) any liability of others of the type
described in the preceding clause (a) or (b) in respect of which that Person has
incurred, assumed or acquired a liability by means of a Guaranty.

                  "Information" means written information, including (a) data,
certificates, reports and statements and (b) summaries of unwritten agreements,
arrangements, contracts, plans, policies, programs or practices or of unwritten
amendments or modifications of, supplements to or waivers under any of the
foregoing documents.

                  "Intellectual Property" means (a) patents, applications for
patents and patent rights, (b) in each case, whether registered, unregistered or
under pending registration, trademark rights, trade names, trade name rights,
service marks, logos, brand names, corporate names,



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business names, trade styles or dress, and copyrights and (c) trade secrets and
know-how and rights in any jurisdiction to limit the use or disclosure thereof
by any Person.

                  "IRS" means the Internal Revenue Service.

                  "Lien" means, with respect to any property or asset of any
Person (or any revenues, income or profits of that Person therefrom) (in each
case whether the same is consensual or nonconsensual or arises by contract,
operation of law, legal process or otherwise), any mortgage, lien, security
interest, pledge, attachment, levy or other charge or encumbrance of any kind
thereupon or in respect thereof.

                  "Litigation" means any action, case, proceeding, claim,
grievance, suit or investigation or other proceeding conducted by or pending
before any Governmental Authority or any arbitration proceeding.

                  "Material" means, as applied to any Entity, material to the
business, operations, property or assets, liabilities, condition (financial or
otherwise) or results of operations of that Entity, as the case may be.

                  "Material Adverse Effect" means, with respect to any Entity,
the result of one or more events, changes or effects which, individually or in
the aggregate, would have a material adverse effect on the business, operations,
property or assets, liabilities or condition (financial or otherwise) of that
Entity and its Subsidiaries taken as a whole, except for (i) any event, change
or effect resulting from general economic, financial or market conditions or
(ii) any event, change or effect resulting from conditions or circumstances
generally affecting the engineering and construction industry.

                  "Material Contract" has the meanings specified in Section
5.11.

                  "Organization State" means, as applied to (a) any corporation,
its state or other jurisdiction of incorporation or (b) any limited liability
company or limited partnership, the state or other jurisdiction under whose laws
it is organized and existing in that legal form.

                  "Other Financing Transaction" means a transaction in which
CB&I sells shares of CB&I Stock to a third party and uses the proceeds to fund a
portion of the PDM Acquisition.

                  "PDM" has the meaning specified in the first paragraph.

                  "PDM Acquisition" has the meaning specified in the
Introduction.

                  "PDM Financing Shares" has the meaning specified in the
Introduction.

                  "Permitted Liens" means, as applied to the property or assets
of any Person (or any revenues, income or profits of that Person therefrom): (a)
Liens for Taxes if the same are not at the time due and delinquent; (b) Liens of
carriers, warehousemen, mechanics, laborers and materialmen for sums not yet
due; (c) Liens incurred in the ordinary course of that Person's business in
connection with workmen's compensation, unemployment insurance and other social
security legislation (other than pursuant to ERISA or Section 412(n) of the
Code); (d) Liens



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incurred in the ordinary course of that Person's business in connection with
deposit accounts or to secure the performance of bids, tenders, trade contracts,
statutory obligations, surety and appeal bonds, performance and return-of-money
bonds and other obligations of like nature; (e) easements, rights-of-way,
reservations, restrictions and other similar encumbrances incurred in the
ordinary course of that Person's business or existing on property and not
Materially interfering with the ordinary conduct of that Person's business or
the use of that property; (f) defects or irregularities in that Person's title
to its real properties that do not Materially (i) diminish the value of the
surface estate or (ii) interfere with the ordinary conduct of that Person's
business or the use of any of such properties; and (g) any interest or title of
a lessor of assets being leased by any Person pursuant to any capital lease or
any lease that, pursuant to GAAP, would be accounted for as an operating lease.

                  "Person" means any natural person, Entity, estate, trust,
union or employee organization or Governmental Authority.

                  "Plan" means any stock purchase, stock option, pension,
profit-sharing, bonus, deferred compensation, incentive compensation,
commission, severance or termination pay, hospitalization, medical, dental, life
or other insurance, or supplemental unemployment benefits plan or agreement or
policy or contract or other arrangement providing employment-related
compensation or benefits to any officer, consultant, director, annuitant,
employee, former employee, retiree or independent contractor or members of their
respective families (other than directors' and officers' liability policies),
whether or not insured, sponsored or maintained by, or under which any
liability, contingent or otherwise, exists with respect to CB&I or its
Subsidiaries, including but not limited to "employee benefit plans" as defined
in ERISA and the rules and regulations thereunder.

                  "Purchase Price" has the meaning specified in Section 2.02.

                  "RCRA" means the Resource Conservation and Recovery Act of
1976, as amended. (42 U.S.C. 6901 et seq.).

                  "Recapitalization" means any stock split, stock dividend,
stock combination, a significant recapitalization, reorganization, or
restructuring, or similar event involving CB&I or any Significant Subsidiary (as
defined in Regulation S-X of the Commission) of CB&I.

                  "Representatives" means, with respect to any Person, the
directors, officers, employees, Affiliates, accountants (including independent
certified public accountants), advisors, attorneys, consultants or other agents
of that Person, or any other representatives of that Person or of any of those
directors, officers, employees, Affiliates, accountants (including independent
certified public accountants), advisors, attorneys, consultants or other agents.

                  "Rights Agreements" has the meaning specified in Section 5.06.

                  "SEC" means the United States Securities and Exchange
Commission.

                  "SEC Documents" has the meaning specified in Section 5.04.



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                  "Securities" means (i) any and all securities issued and
outstanding by CB&I at any time, (ii) any shares of stock issued or issuable in
respect of such securities and (iii) any right to acquire by contract or
otherwise from CB&I or any Person, and whether or not then exercisable, any
security described in (i) or (ii).

                  "Securities Act" means the Securities Act of 1933, as amended.

                  "Shareholder Agreement" means the Shareholder Agreement, dated
December 28, 2000, as amended, between WEDGE Group Incorporated and CB&I.

                  "Solid Wastes, Hazardous Wastes or Hazardous Substances" have
the meanings ascribed to those terms in CERCLA, RCRA or any other Environmental
Law applicable to the business or operations of CB&I and its Subsidiaries that
imparts a broader meaning to any of those terms than does CERCLA or RCRA,
including but not limited to (i) petroleum and petroleum products, including
crude oil and any fractions thereof, (ii) asbestos, (iii) PCBs, and (iv) natural
gas, synthetic gas and any mixtures thereof.

                  "Subsidiary" of any specified Person at any time means any
Entity a majority of the Capital Stock of which is at that time owned or
controlled, directly or indirectly, by the specified Person.

                  "Tax" or "Taxes" means all net or gross income, gross
receipts, net proceeds, sales, use, ad valorem, value added, franchise, bank
shares, withholding, payroll, employment, excise, property, deed, stamp,
alternative or add-on minimum, environmental or other taxes, assessments,
duties, fees, levies or other governmental charges or assessments of any nature
whatsoever imposed by any Governmental Requirement, whether disputed or not,
together with any interest, penalties, additions to tax or additional amounts
with respect thereto.

                  "Tax Return" means any report, return, information statement,
payee statement or other information required to be provided to any federal,
state, local or foreign Taxing Authority, or otherwise retained, with respect to
Taxes.

                  "Taxing Authority" means any Governmental Authority having or
purporting to exercise jurisdiction with respect to any Tax.

                  "Transaction Documents" means this Agreement, Funding
Agreement, the Amendment to the Shareholder Agreement and the other written
agreements, documents, instruments and certificates executed pursuant to or in
connection therewith, including those specified or referred to in Article III or
Article VII to be delivered at or before the Closing, all as amended, modified
or supplemented from time to time.

                  "Worker Safety Laws" shall mean all applicable Governmental
Requirements relating to public and worker health and safety.

          Section 1.02 Other Defined Terms. Words and terms used in this
Agreement that are defined elsewhere in this Agreement are used as so defined.



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          Section 1.03 Cross References, Interpretation. References to
"Articles" refer to Articles of this Agreement. References to "Sections" refer
to Sections and subsections of this Agreement. Whenever the singular number is
used in this Agreement and when required by the context, the same shall include
the plural and vice versa, and the masculine gender shall include the feminine
and neuter genders and vice versa. Whenever the word "including" is used in this
Agreement, it shall be read to mean "including but not limited to." The headings
in this Agreement are inserted for convenience only and are not intended to
describe, interpret, define or limit the scope, extent or intent of this
Agreement or any provision hereof.

          Section 1.04 Knowledge. Where any statement is qualified by the
expression "to CB&I's knowledge" or by a similar expression, that statement
shall be deemed to be the actual personal knowledge, after due inquiry of the
relevant senior operating employees of CB&I and the applicable CB&I Subsidiary,
of Gerald M. Glenn, Richard E. Goodrich, Robert B. Jordan, Timothy J. Wiggins or
Robert H. Wolfe.

                                   ARTICLE II

                                PURCHASE AND SALE


          Section 2.01 Purchase and Sale of PDM Financing Shares. Upon the terms
and subject to the satisfaction of the conditions contained in this Agreement,
at the Closing CB&I shall sell, convey, assign, transfer and deliver to WEDGE,
and WEDGE shall purchase and acquire from CB&I, by delivery of the Purchase
Price (as hereinafter defined), the PDM Financing Shares.

          Section 2.02 Payment of Purchase Price. In consideration of the sale
of the PDM Financing Shares by CB&I to WEDGE, WEDGE shall pay to CB&I in
immediately available funds, by wire transfer, Thirteen Million Six Hundred
Twelve Thousand and Five Hundred U.S. Dollars (U.S. $13,612,500) at the Closing
(the "Purchase Price").

                                  ARTICLE III

                                     CLOSING


          Section 3.01 Other Transactions. In connection with the Closing, the
PDM Acquisition and the Other Financing Transaction shall be consummated.
Simultaneously with the Closing, the Amendment to the Shareholder Agreement and
Funding Agreement shall be executed.

          Section 3.02 The Effective Time. The effective time of the purchase of
the PDM Financing Shares (the "Effective Time") will be 5:00 p.m., Central
Daylight Time, on the Closing Date.

          Section 3.03 The Closing. The closing of the transactions contemplated
herein shall take place at the offices of Winston & Strawn, 35 West Wacker
Drive, Chicago, Illinois, at 10:00 a.m., local time, on a date within ten
business days following satisfaction of each of the conditions set forth in
Sections 7.01 and 7.03(c) (assuming satisfaction of the remaining conditions set
forth in Article VII on or prior to the Closing Date), or such other place or
time as


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the parties may mutually agree (the "Closing Date"). On or before the Closing
Date, the parties hereto will take all actions necessary to (i) effect the PDM
Acquisition, (ii) effect the Purchase and Sale of the PDM Financing Shares;
(iii) effect the Other Financing Transaction, and (iv) satisfy the document
delivery requirements on which the obligations of the parties to effect the PDM
Acquisition, the transactions contemplated by this Agreement and the Other
Financing Transaction, and the other transactions contemplated hereby are
conditioned by the provisions of Article VII (all those actions collectively
being the "Closing").

          Section 3.04 Delivery of Documents. (a) At the Closing, CB&I will
execute and deliver to WEDGE the following documents:

                  (i) certificates representing the PDM Financing Shares;

                  (ii) the Funding Agreement;

                  (iii) a copy, certified as of the Closing Date, by the
Secretary or Assistant Secretary of CB&I of resolutions duly adopted by the
Supervisory Board of Directors of CB&I authorizing the transactions contemplated
by this Agreement, the Funding Agreement and the PDM Acquisition;

                  (iv) an extract from the trade register regarding CB&I as of a
recent date provided by the Chamber of Commerce and Industry in Amsterdam (the
"Chamber of Commerce");

                  (v) an official copy of the amended Articles of Association of
CB&I filed with the Chamber of Commerce as reflected in the extract referred to
above;

                  (vi) certificate of the Secretary or Assistant Secretary of
CB&I certifying as of the Closing Date the incumbency and signatures of the
Managing Director of CB&I authorized to sign this Agreement, the Funding
Agreement and the other documents to be delivered hereunder and thereunder and
in connection with the PDM Acquisition, together with evidence of the incumbency
of such Secretary or Assistant Secretary or similar authorized person;

                  (vii) the Amendment to the Shareholder Agreement executed by
CB&I;

                  (viii) the opinion or opinions of CB&I's legal counsel
substantially in the form of Exhibit B and Exhibit C; and

                  (ix) any non-governmental, third party consents required for
the consummation of the transactions contemplated hereby (including, without
limitation, the executed, written consent of CB&I's bank group referred to in
Section 5.21).

          (b) At the Closing, WEDGE will cause to be executed and delivered to
CB&I the following:

                  (i) the Purchase Price;

                  (ii) the Funding Agreement;



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                  (iii) the Amendment to the Shareholder Agreement executed by
WEDGE;

                  (iv) a copy of the power of attorney granted by the Managing
Director of WEDGE relating to the transactions contemplated hereby; and

                  (v) any non-governmental, third-party consents required to be
obtained by WEDGE for the consummation by WEDGE of the transactions contemplated
hereby.

                                   ARTICLE IV

                     REPRESENTATIONS AND WARRANTIES OF WEDGE


As an inducement to CB&I to enter into this Agreement and to consummate the
transactions contemplated hereby, WEDGE represents and warrants to the CB&I as
follows:

          Section 4.01 Corporate Power and Authority. WEDGE has all requisite
power, authority and legal right to execute, deliver, enter into, consummate the
transactions contemplated by and perform its obligations under this Agreement.
The execution, delivery and performance of this Agreement by WEDGE have been
duly authorized by all required corporate and other actions. WEDGE has duly
executed and delivered this Agreement and this Agreement constitutes the legal,
valid and binding obligations of WEDGE enforceable against WEDGE in accordance
with its terms, subject to bankruptcy, insolvency, reorganization, moratorium,
fraudulent transfer and other similar laws relating to the rights of creditors
generally from time to time in effect and to general principles of equity,
including without limitation, concepts of materiality, reasonableness, good
faith and fair dealing, regardless of whether in a proceeding in equity or at
law.

          Section 4.02 Investment Representations. (a) WEDGE understands that
the offer, sale and transfer of the shares of CB&I Stock to be issued to WEDGE
hereunder (i) have not been registered with the SEC or pursuant to any state
securities laws in reliance on the exemption afforded by Section 4(2) of the
Securities Act and comparable exemptions from applicable state laws, and (ii)
that such shares will be restricted securities under the Securities Act and
various states' securities laws, and that these laws impose limitations on the
Persons to whom sales of shares may be made. The certificates representing
shares of the CB&I Stock to be delivered to WEDGE as the PDM Financing Shares
will bear a legend substantially as follows:

          "THE ISSUANCE OF THE SHARES REPRESENTED HEREBY HAS NOT BEEN REGISTERED
          UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT") OR ANY STATE
          SECURITIES LAWS. SUCH SHARES MAY NOT BE OFFERED, SOLD, TRANSFERRED (BY
          MERGER OR OTHERWISE), ASSIGNED, DEVISED, EXCHANGED, GIFTED, PLEDGED,
          HYPOTHECATED OR OTHERWISE DISPOSED OF UNLESS AND UNTIL REGISTERED
          UNDER THE ACT AND ANY APPLICABLE STATE SECURITIES LAWS OR UNLESS SUCH
          TRANSFER IS EXEMPT FROM REGISTRATION, AND CHICAGO BRIDGE & IRON
          COMPANY N.V. (THE "COMPANY") SHALL HAVE BEEN FURNISHED WITH AN OPINION
          OF COUNSEL, SATISFACTORY TO THE COMPANY, TO SUCH EFFECT.



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          THE SHARES EVIDENCED BY THIS CERTIFICATE ARE SUBJECT TO THE
          RESTRICTIONS ON TRANSFER AS SET FORTH IN THAT CERTAIN SHAREHOLDER
          AGREEMENT DATED AS OF DECEMBER 28, 2000, AS AMENDED, BETWEEN THE
          COMPANY AND WEDGE GROUP INCORPORATED (THE "SHAREHOLDER AGREEMENT"). NO
          TRANSFER OF THESE SHARES WILL BE EFFECTIVE UNLESS AND UNTIL THE TERMS
          AND CONDITIONS OF SUCH SHAREHOLDER AGREEMENT HAVE BEEN COMPLIED WITH
          IN FULL AND NO PERSON MAY REQUEST THE COMPANY TO RECORD THE TRANSFER
          OF ANY SHARES IF SUCH TRANSFER IS IN VIOLATION OF SUCH SHAREHOLDER
          AGREEMENT. A COPY OF THE SHAREHOLDER AGREEMENT IS ON FILE AT THE
          ADMINISTRATIVE OFFICES OF THE COMPANY IN PLAINFIELD, ILLINOIS AND WILL
          BE FURNISHED WITHOUT CHARGE TO THE HOLDER OF SUCH SHARES UPON WRITTEN
          REQUEST. THE SHARES EVIDENCED BY THIS CERTIFICATE ARE SUBJECT TO
          RESTRICTIONS ON VOTING PROVIDED FOR IN THE SHAREHOLDER AGREEMENT AND
          NO VOTE OF SUCH SHARES THAT CONTRAVENES THE SHAREHOLDER AGREEMENT
          SHALL BE EFFECTIVE."

          (b) WEDGE represents that it (i) is an "accredited investor" (as
defined in Rule 501(a)(3) under the Securities Act, (ii) has such knowledge,
sophistication and experience in financial and business matters as to be capable
of evaluating the merits and risks of its investment in the CB&I Stock, and
(iii) is able to bear the economic risk of its investment in the CB&I Stock.
WEDGE is acquiring the CB&I Stock for its own account for investment and
(subject to the disposition of its property being at all times within its
control) not with a present view to, or for sale or other disposition in
connection with, any distribution of all or any part of such CB&I Stock. WEDGE
acknowledges that (x) neither CB&I nor any Person representing CB&I has made any
representation to WEDGE with respect to CB&I or the CB&I Stock other than as
contained in this Agreement and (y) WEDGE has had access to such financial and
other information concerning CB&I and the CB&I Stock as WEDGE has deemed
necessary in connection with its investment decision to purchase the CB&I Stock,
including an opportunity to ask questions of and request information from CB&I.

          (c) Notwithstanding anything to the contrary in this Section 4.02,
WEDGE is not waiving any of its rights or remedies under this Agreement or the
Shareholder Agreement or any representations, warranties or obligations of CB&I
under this Agreement (including the terms of Article V and Article IX) or the
Shareholder Agreement.

          Section 4.03 Brokers. No broker, finder or investment banker or other
party is entitled to any brokerage, finder's or other similar fee or commission
in connection with this Agreement, or any of the transactions contemplated
hereby or thereby, based upon arrangements made by or on behalf of WEDGE or any
of its Subsidiaries or Affiliates.

          Section 4.04 Limitations on Representations and Warranties. Except as
and to the extent expressly set forth in this Article IV, included on any
Schedule hereto or included in any writing delivered by WEDGE concurrently
herewith or subsequent hereto expressly pursuant to



                                       11
   13

this Agreement, WEDGE makes no other representations or warranties, and
disclaims all liability and responsibility for any representation, warranty,
statement or information made or communicated (orally or in writing) to CB&I or
any of its Affiliates, employees, agents, consultants or representatives
(including, without limitation, any opinion, information, projection or advice
that may have been provided to CB&I by any officer, director, employee, agent,
consultant or representative of WEDGE or any Affiliate thereof, or by any other
agent, consultant or representative of WEDGE).

                                    ARTICLE V

                     REPRESENTATIONS AND WARRANTIES OF CB&I


                  As an inducement to WEDGE to enter into this Agreement and to
consummate the transactions contemplated hereby, CB&I represents and warrants to
WEDGE as follows:

          Section 5.01 Organization; Power. (a) CB&I is an N.V. company duly
organized and validly existing under the laws of the Netherlands. CB&I has all
requisite corporate power and authority under the laws of its Organization State
and its Charter Documents to own or lease and to operate its properties
presently and following the Effective Time and to carry on its business as now
conducted and as proposed to be conducted following the Effective Time.

          (b) A true and complete list of each Material CB&I subsidiary,
together with its Organization State and the percentage of its outstanding
Capital Stock owned by CB&I and any other CB&I Subsidiary, is set forth in
Schedule 5.01. Except as disclosed in Schedule 5.01, CB&I does not directly or
indirectly own any equity or similar interest in, or any interest convertible
into or exchangeable or exercisable for, any equity or similar interest in, any
Entity which is Material to CB&I. Except as set forth in the SEC Documents or
Schedule 5.01, neither CB&I nor any of its Subsidiaries is subject to any
obligation to make any Material investment in any other Person.

          Section 5.02 Authorization; Enforceability; Absence of Conflicts;
Required Consents. (a) CB&I has full corporate authority to enter into this
Agreement, the Amendment to the Shareholder Agreement and the other Transaction
Documents and to perform its obligations hereunder and thereunder. The execution
and delivery of this Agreement, the Amendment to the Shareholder Agreement and
the consummation of the transactions contemplated hereby have been duly
authorized by all necessary action on the part of CB&I, and this Agreement has
been duly executed and delivered by CB&I. This Agreement constitutes, and the
Amended Shareholder Agreement and Funding Agreement when executed and delivered
will constitute, the legal, valid and binding obligation of CB&I, enforceable
against it in accordance with its terms, except that enforceability may be (i)
limited by any applicable bankruptcy, insolvency, reorganization, moratorium or
similar laws affecting the enforcement of creditors' rights generally and (ii)
subject to general principles of equity (regardless of whether that
enforceability is considered in a proceeding in equity or at law).

          (b) The execution, delivery and performance in accordance with their
respective terms by CB&I of this Agreement, the Amendment to the Shareholder
Agreement and the other



                                       12
   14

Transaction Documents to which it is a party have not and will not (i) violate,
breach or constitute a default under (A) its Charter Documents, (B) any
Governmental Requirement, order, writ, injunction or decree applicable to it, or
(C) any note, bond, mortgage, indenture or material agreement or obligation to
which it is a party or by which it is bound, except for such violations,
breaches, terminations, and defaults that are set forth in Schedule 5.02, (ii)
result in the acceleration or mandatory prepayment of any Indebtedness, or any
Guaranty not constituting Indebtedness, of CB&I, or afford any holder of any of
that Indebtedness, or any beneficiary of any of those Guaranties, the right to
require CB&I to redeem, purchase or otherwise acquire, reacquire or repay any of
that Indebtedness, or to perform any of those Guaranties, (iii) cause or result
in the imposition of, or afford any Person the right to obtain, any Lien upon
any property or assets of CB&I (or upon any revenues, income or profits of CB&I
therefrom), except for certain covenants of CB&I contained in its bank credit
facilities, or (iv) result in the revocation, cancellation, suspension or
material modification, in any single case or in the aggregate, of any
Governmental Approval possessed by CB&I at the date hereof and necessary for the
ownership or lease and the operation of its properties or the carrying on of its
business as now conducted, including any necessary Governmental Approval under
any applicable Environmental Law.

          (c) Except (i) as may be required by the HSR Act or applicable state
securities or blue sky laws or (ii) as set forth in Schedule 5.02, no
Governmental Approvals or consents of any third party are required to be
obtained, and no reports or notices to or filings with any Governmental
Authority are required to be made, by CB&I for the execution, delivery or
performance by CB&I of this Agreement, the Amendment to the Shareholder
Agreement or the other Transaction Documents to which it is a party, the
enforcement against CB&I of its obligations hereunder or thereunder or the
effectuation of the PDM Acquisition and the transactions contemplated hereby and
thereby.

          Section 5.03 Charter Documents. No breach or violation of any Charter
Document of CB&I has occurred and is continuing that could reasonably be
expected to have a Material Adverse Effect.

          Section 5.04 SEC Documents. CB&I has made available to WEDGE a true
and complete copy of each report, schedule, registration statement and
definitive proxy statement filed by CB&I with the SEC since January 1, 1998 and
prior to the date of this Agreement (the "SEC Documents") which are all the
documents (other than preliminary material) that CB&I has been required to file
with the SEC since such date. As of their respective dates, the SEC Documents
complied in all material respects with the requirements of the Securities Act or
the Exchange Act, as the case may be, and the rules and regulations of the SEC
thereunder applicable to such SEC Documents, and none of the SEC Documents
contained any untrue statement of a material fact or omitted to state a material
fact required to be stated therein or necessary to make the statements therein,
in light of the circumstances under which they were made, not misleading. The
financial statements of CB&I contained in the SEC Documents complied as to form
in all material respects with the published rules and regulations of the SEC
with respect thereto, were prepared in accordance with GAAP applied on a
consistent basis during the periods involved (except as may be indicated in the
notes thereto or, in the case of the unaudited statements, as permitted by Rule
10-01 of Regulation S-X of the SEC) and fairly present in accordance with
applicable requirements of GAAP (subject, in the case of the unaudited
statements, to normal, recurring adjustments, none of which will be Material)
the



                                       13
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consolidated financial position of CB&I and its consolidated Subsidiaries as of
their respective dates and the consolidated results of operations and the
consolidated cash flows of CB&I and its consolidated Subsidiaries for the
periods presented therein, respectively.

          Section 5.05 Capitalization. The capitalization of CB&I is set forth
on Schedule 5.05. As of the Closing Date, all of the PDM Financing Shares will
be duly authorized for issuance and will be validly issued, fully paid and
nonassessable. Except as set forth in Schedule 5.05, there are no outstanding
subscriptions, options, warrants, calls or rights of any kind to acquire any
shares of any class of securities or any securities convertible into any shares
of any class of securities of CB&I, nor are there any obligations to issue any
such options, warrants, calls, rights or securities. There are no restrictions
of any kind on the transfer by CB&I to WEDGE of the PDM Financing Shares, except
as may be imposed by applicable securities laws. Schedule 5.05 sets forth
certain capitalization figures for CB&I as of various relevant dates and events.

          Section 5.06 Absence of Applicable Rights Agreements. Except as set
forth in CB&I's 2000 Proxy Statement or on Schedule 5.06, there are no rights
agreements or other agreements by or between CB&I and any of its shareholders
that could ultimately result in the grant of additional shares of CB&I Stock,
additional rights to purchase any such CB&I Stock, any new class or type of
security of CB&I or other rights or benefits to CB&I's shareholders as of the
date hereof ("Rights Agreements") which would apply to the execution and
delivery of this Agreement, the issuance to WEDGE of the PDM Financing Shares,
the execution and delivery of the Amendment to the Shareholder Agreement or any
other transaction contemplated hereby or thereby. Further, no such grant of
additional shares of CB&I Stock, additional rights to purchase any such CB&I
Stock, any new class or type of security of CB&I or other rights or benefits to
CB&I's shareholders as of the date hereof will result by operation of (i) the
law of CB&I's Organization State, (ii) any provision of its Charter Documents or
(iii) any combination thereof.

          Section 5.07 Litigation. Except as set forth in the SEC Documents or
on Schedule 5.07, no Litigation is pending or, to the knowledge of CB&I,
threatened to which CB&I or any of its Subsidiaries is or may become a party
that (a) questions or involves the validity or enforceability of any obligation
of CB&I under any Transaction Document, (b) seeks (or reasonably may be expected
to seek) (i) to prevent or delay consummation by CB&I of the transactions
contemplated by this Agreement to be consummated by CB&I or (ii) Damages from
CB&I in connection with any such consummation, or (c) which would have, or would
reasonably be expected to have, individually or in the aggregate, a Material
Adverse Effect. No Governmental Authority has provided notification to CB&I or
any of its Subsidiaries of an intention to conduct any audit, investigation or
other review with respect to CB&I or any of its Subsidiaries, which audit,
investigation or review would, if adversely determined, individually or in the
aggregate, have a Material Adverse Effect on CB&I.

          Section 5.08 Compliance with Worker Safety and Environmental Laws.
Except as disclosed in the SEC Documents or on Schedule 5.08: (a) CB&I and its
Subsidiaries have complied and remain in compliance in all material respects
with all applicable Environmental Laws and all applicable Worker Safety Laws,
except for any such noncompliance which would have no Material Adverse Effect;
(b) no release of Solid Wastes, Hazardous Wastes or Hazardous Substances at,
from, in or on any site owned or operated by CB&I or its Subsidiaries as of the
Closing Date has occurred that, if all relevant facts were known to the relevant



                                       14
   16


Governmental Authorities, reasonably could be expected to require remediation to
avoid deed record notices, restrictions, liabilities or other consequences that
would not be applicable if that release had not occurred; (c) neither CB&I, its
Subsidiaries nor any agent or contractor of CB&I or its Subsidiaries has
transported or arranged for the transportation of any Solid Wastes, Hazardous
Wastes or Hazardous Substances to, or disposed or arranged for the disposition
of any Solid Wastes, Hazardous Wastes or Hazardous Substances at, any off-site
location that could lead to any claim against CB&I or its Subsidiaries, as a
potentially responsible party, for any cleanup costs, remedial work, damage to
natural resources, personal injury or property damage, including any claim under
CERCLA; (d) no storage tanks exist on or under any of the properties owned or
operated by CB&I or its Subsidiaries as of the Closing Date from which any Solid
Wastes, Hazardous Wastes or Hazardous Substances have, to the knowledge of CB&I,
been released into the surrounding environment; and (e) no Solid Wastes,
Hazardous Wastes or Hazardous Substances have been used, stored, manufactured or
processed on the property owned, used, leased or operated by CB&I or any of its
current or former Subsidiaries at any time, except as necessary to the conduct
of its business in compliance with Environmental Laws and Worker Safety Laws and
except where any noncompliance would not have a Material Adverse Effect.

          Section 5.09 Liabilities and Obligations. There are no Material
liabilities of any kind, character and description and whether accrued,
absolute, or fixed, of CB&I that (a) reasonably could be expected to have a
Material Adverse Effect on CB&I other than as set forth on Schedule 5.09 or as
disclosed in the SEC Documents, and (b) (i) had been incurred prior to the most
recent SEC Document but are not reflected on that SEC Document or (ii) were
incurred after the most recent SEC Document otherwise than in the ordinary
course of business and consistent with past practice.

          Section 5.10 Intellectual Property. To the knowledge of CB&I, except
as set forth in Schedule 5.10, CB&I or its Subsidiaries owns, free and clear of
all Liens other than Permitted Liens, or has the legal right to use, all
Intellectual Property that is necessary to the conduct of its business as now
conducted, in each case free of any claims or infringements. Schedule 5.10 (a)
lists the Material Intellectual Property of CB&I and its Subsidiaries and (b)
indicates that owned by CB&I or its Subsidiaries and, for those not listed as so
owned, the agreement or other arrangement pursuant to which they are possessed.
Except as set forth in Schedule 5.10, to the knowledge of CB&I, (a) no consent
of any Person will be required for the use of any of this Material Intellectual
Property by CB&I or any Subsidiary of CB&I following the Effective Time and (b)
no governmental registration of any of this Material Intellectual Property has
lapsed or expired or been canceled, abandoned, opposed or has been the subject
of any reexamination request.

          Section 5.11 Material Contracts. Schedule 5.11 sets forth a complete
list of all Material Contracts (as defined below) not listed on the Exhibit
Index to CB&I's Form 10-K Annual Report for the fiscal year ended December 31,
1999, previously made available to WEDGE. Each such Material Contract is in full
force and effect and is enforceable against the parties thereto other than CB&I
and its Subsidiaries in accordance with its terms, and no condition or state of
facts exists that, with notice or the passage of time or both, would constitute
a material default by CB&I or its applicable Subsidiary or, to the knowledge of
CB&I, any third party under any such Material Contract. CB&I or its applicable
Subsidiary has duly complied in all



                                       15
   17

material respects with the provisions of each such Material Contract to which it
is a party. For the purpose of this Agreement, a Material Contract with respect
to CB&I or its Subsidiaries shall mean:

                  (i) those material agreements required to be filed by CB&I
pursuant to applicable SEC rules and regulations;

                  (ii) any instrument, agreement or other obligation evidencing
or relating to Indebtedness of CB&I or any of its Subsidiaries or to money lent
or to be lent to another Person involving more than $500,000; and

                  (iii) any agreement for the acquisition or provision of
services, supplies, equipment, inventory, fixtures or other property involving
more than $500,000 individually the costs for which are not passed through to
the customers of CB&I or its Subsidiaries in the ordinary course of business,
and all earnout agreements.

          Section 5.12 Insurance. Schedule 5.12 sets forth a list of all
insurance policies currently in force carried by CB&I or its Subsidiaries which
relate to their business. CB&I has previously made available to WEDGE (a) a
complete list of all insurance loss runs and worker's compensation claims
relating to CB&I's business and received for the most recently ended two (2)
policy years, and (b) true, complete and correct copies of all insurance
policies, binders or similar documentation carried by CB&I that relate to CB&I's
business and are in effect, all of which (i) have been issued by insurers of
recognized responsibility and (ii) currently are, and will remain without
interruption to the Effective Time, in full force and effect.

          Section 5.13 Employee Matters. (a) Employment Agreements. Schedule
5.13(a) contains a list of all of the following, whether written or unwritten:
(i) Employment Agreements and (ii) plans, programs, agreements and other
arrangements with or relating to employees containing change of control or
similar provisions not otherwise listed in the SEC Documents remaining executory
in whole or in part on the date hereof, and CB&I has provided WEDGE with true,
complete and correct copies of all those Employment Agreements and such plans,
programs, agreements and other arrangements. CB&I is not party to any oral
Employment Agreement.

          (b) Employee Benefit Plans. For purposes of this Section 5.13 and
Section 5.14, all references to "CB&I" shall be deemed to refer to CB&I and its
Subsidiaries and any trade or business, whether or not incorporated, that
together with CB&I and its Subsidiaries would be deemed or treated as a "single
employer" within the meaning of ERISA Section 4001 or Code Section 414.

                  (i) Each Plan is listed on Schedule 5.13(b). Except as
discussed on Schedule 5.13(b), no Plan is or has been (w) covered by Title IV of
ERISA, (x) subject to the minimum funding requirements of Section 412 of the
Code, (y) a "multi-employer plan" as defined in Section 3(37) of ERISA or (z) a
voluntary employees' beneficiary association within the meaning of Code Section
501(c)(9).

                  (ii) Except as described on Schedule 5.13(b), (x) CB&I has no
obligation to make any payments that would be "excess parachute payments" under
Section 280G of the Code;



                                       16
   18

and (y) no Plan provides for the continuation of medical or health benefits or
death benefits after an employee's termination of employment (including
retirement) other than (A) coverage mandated by applicable law, (B) deferred
compensation benefits reflected as liabilities on the books of CB&I or (C)
benefits the full cost of which is borne by the current or former employee or
his beneficiary.

          Section 5.14 Compliance With ERISA, Labor Laws. (a) Each Plan complies
in form and operation in all material respects with its governing documents and
ERISA, the Code and all other applicable Governmental Requirements except where
such noncompliance would not have a Material Adverse Effect. CB&I has no
commitment or obligation to establish or adopt any new or additional Plans or to
Materially increase the benefits under any existing Plan.

          (b) To the knowledge of CB&I, with respect to the Plans, no event has
occurred and there exists no condition or set of circumstances in connection
with which CB&I could be subject to any liability (except for contributions and
Plan expenses) under the terms of such Plans, ERISA, the Code or any other
applicable law except where such failure would not have a Material Adverse
Effect. All Plans that are intended to be qualified under Section 401(a) of the
Code have been determined by the IRS to be so qualified, and nothing has
occurred to the knowledge of CB&I since the date of determination which could
cause any such Plan to be disqualified.

          (c) Except as set forth on Schedule 5.14, neither CB&I nor any of its
Subsidiaries is a party to any Material collective bargaining agreement or labor
contract. Except as set forth on Schedule 5.14, to the knowledge of CB&I,
neither CB&I nor any of its Subsidiaries has engaged in any unfair labor
practice with respect to any Persons employed by or otherwise performing
services primarily for CB&I or any of its Subsidiaries. Except as set forth on
Schedule 5.14, there is no grievance or unfair labor practice charge against
CB&I or any of its Subsidiaries before the National Labor Relations Board or any
comparable state agency pending or threatened in writing with respect to any
such Persons. There is no labor strike, dispute (to the knowledge of CB&I),
slowdown, work stoppage, and, to the knowledge of CB&I, there is not threatened
nor has there been threatened, any organizing effort or activity by any
employees or labor unions at or relating to CB&I or any of its Subsidiaries, any
petition for certification of a collective bargaining representative regarding
employees of CB&I or any of its Subsidiaries, pending or, to the knowledge of
CB&I, threatened against or affecting CB&I or any of its Subsidiaries which
would have a Material Adverse Effect.

          Section 5.15 Absence of Changes. Since the most recent SEC Document,
except as set forth in Schedule 5.15, none of the following has occurred with
respect to CB&I's business:

          (a) any increase in, or any commitment or promise to increase, other
than ordinary and customary bonuses and salary increases for employees at the
times and in the amounts consistent with its past practice, (i) the rates of
cash compensation or (ii) except as would not have a Material Adverse Effect on
CB&I or as required by applicable laws, any increase in the amounts or other
benefits paid or payable under any Plans;



                                       17
   19


          (b) any work interruptions, labor grievances or claims filed, or any
similar event or condition of any character, that will have a Material Adverse
Effect on CB&I following the Effective Time;

          (c) any distribution, sale or transfer of, or any commitment to
distribute, sell or transfer, assets of CB&I or any of its Subsidiaries of any
kind that singly is, or in the aggregate are, Material to CB&I's business, other
than distributions, sales or transfers in the ordinary course of its business
and consistent with its past practices;

          (d) any cancellation, or agreement to cancel, any Material
Indebtedness, obligation or other liability owing to CB&I or its Subsidiaries,
including any Material Indebtedness, obligation or other liability of any
Affiliate, provided that CB&I and its Subsidiaries may negotiate and adjust
bills and invoices in the course of good-faith disputes with customers in a
manner consistent with past practice;

          (e) any plan, agreement or arrangement granting any preferential
rights to purchase or acquire any interest in any of the Material assets of CB&I
or its Subsidiaries or requiring the consent of any Person to the transfer and
assignment of any of such asset;

          (f) any purchase or acquisition of, or agreement, plan or arrangement
to purchase or acquire, any property, rights or assets outside of the ordinary
course of operating CB&I's business consistent with its past practices;

          (g) any waiver of any of the rights or claims of CB&I or its
Subsidiaries that singly is, or in the aggregate are, Material to CB&I's
business;

          (h) any transaction by CB&I or its Subsidiaries outside the ordinary
course of operating CB&I's business or not consistent with the past practices of
its business;

          (i) any incurrence by CB&I or its Subsidiaries of any of the
following: any Material Indebtedness or any Material Guaranty not constituting
Indebtedness, or any commitment to incur any such Indebtedness or any such
Guaranty (except for CB&I Guaranties of the performance of its Subsidiaries and
Affiliates in the ordinary course of business); or

          (j) any cancellation or termination of a material agreement relating
to CB&I's business.

          Section 5.16 Broker's Fees. CB&I has no liability or obligation to pay
any fees or commissions to any broker, finder or agent with respect to the
transactions contemplated by this Agreement.

          Section 5.17 Inside Information. CB&I has complied with Section 46a of
the Dutch 1995 Securities Act (Wet toezicht effectenverkeer 1995) continuously.
At the time of its entry into this Agreement and at its issuance of the PDM
Financing Shares, CB&I did not possess, and has not provided to WEDGE, any
insider knowledge (voorwetenschap) in respect of it or the trade in its
securities within the meaning of Section 46 of the Dutch 1995 Securities Act
(Wet toezicht effectenverkeer 1995).



                                       18
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          Section 5.18 Change of Control. The consummation of the transactions
contemplated by this Agreement, Funding Agreement, the PDM Acquisition and the
Other Financing Transaction will not trigger any change-of-control provisions in
any Plan or Material Contract.

          Section 5.19 Limitations on Representations and Warranties. Except as
and to the extent expressly set forth in this Article V, included on any
Schedule hereto or included in any writing delivered by CB&I concurrently
herewith or subsequent hereto expressly pursuant to this Agreement, CB&I makes
no other representations or warranties, and disclaims all liability and
responsibility for any representation, warranty, statement or information made
or communicated (orally or in writing) to WEDGE or any of its Affiliates,
employees, agents, consultants or representatives (including any opinion,
information, projection or advice that may have been provided to WEDGE by any
officer, director, employee, agent, consultant or representative of CB&I or any
Affiliate thereof, or by any other agent, consultant or representative of CB&I
or the CB&I Subsidiaries).

                                   ARTICLE VI

                     COVENANTS AND AGREEMENTS OF THE PARTIES


          Section 6.01 Mutual Cooperation. WEDGE and CB&I will cooperate with
each other and their Representatives in the preparation of any documents or
other material that may be required in connection with any Transaction Document.
CB&I and WEDGE will treat all Confidential Information obtained by them in
connection with the negotiation and performance of this Agreement as
confidential in accordance with the provisions of Section 11.01.

          (a) The parties hereby acknowledge that any in-house counsel of WEDGE,
on the one hand, and of CB&I and any CB&I Subsidiary, on the other hand, who are
employees and who participated in the preparation, negotiation or consummation
of this Agreement or the transactions contemplated hereby were providing legal
representation for WEDGE or CB&I, as the case may be, and that, notwithstanding
any other provision of this Agreement, neither WEDGE or its affiliates, CB&I,
any CB&I Subsidiary, nor such counsel shall be required to disclose under any
circumstance any information or documents covered by the attorney-client
privilege or the work-product doctrine as such information or documents were
developed in the course of such representation. All such information and
documents shall remain the sole and exclusive property of WEDGE or CB&I, as the
case may be. Any claims made against such in-house counsel arising out of the
opinions given pursuant to this Agreement shall be treated as a claim against
the party who employed such in-house counsel.

          (b) CB&I and WEDGE will use their best efforts to secure, as soon as
practicable after the date hereof, all approvals and consents of third Persons
as may be necessary to consummate the transactions contemplated hereby.

          (c) If this Agreement is terminated pursuant to Article XII, CB&I and
WEDGE will promptly return all Confidential Information of the other party it
then possesses to such other party.



                                       19
   21


          Section 6.02 Conduct of Business Pending the Closing. From the date
hereof and until the Closing, CB&I will:

          (a) carry on its business in substantially the same manner as it has
heretofore and not introduce any Material new method of management, operation or
accounting;

          (b) perform all its obligations under agreements relating to or
affecting its business consistent with past practices;

          (c) keep in full force and effect without interruption all its present
insurance policies relating to its business and the assets of CB&I or other
comparable insurance coverage;

          (d) use reasonable commercial efforts to (i) maintain and preserve its
business organizations operating its respective business intact, (ii) retain
present key employees who are involved in the operation of its business and
(iii) maintain relationships with suppliers, customers and others having
business relations with its business; and

          (e) comply with all applicable Governmental Requirements relating to
its business.

          Section 6.03 Prohibited Activities.

          From the date hereof and until the Closing, without the prior written
consent of the other parties to this Agreement or unless as required or
expressly permitted by this Agreement, CB&I will not:

          (a) create, assume or permit to be created or imposed any Liens (other
than Permitted Liens) upon any of the assets of CB&I, whether now owned or
hereafter acquired;

          (b) agree to sell, assign, lease or otherwise transfer or dispose of
substantially all of the assets of CB&I or agree to merge, consolidate or effect
a share exchange with, any other Entity;

          (c) commit a Material breach of any Material Contract of CB&I or its
Subsidiaries or of any Governmental Approvals Material to its business;

          (d) enter into any other transactions which would have a Material
Adverse Effect on its business that is not in the ordinary course of its
business and consistent with its past practice or is prohibited hereby; or

          (e) (i) solicit, initiate or encourage, or take any other action to
facilitate, any inquiries or the making of any proposal that constitutes, or may
reasonably be expected to lead to, an Alternative Proposal, or (ii) participate
in any discussions or negotiations regarding an Alternative Proposal.

          Section 6.04 Notification of Certain Matters. WEDGE shall give prompt
notice to CB&I of (a) the existence or occurrence of each condition or state of
facts that will or reasonably could be expected to cause any representation or
warranty of WEDGE contained herein to be untrue or incorrect in any Material
respect at or prior to the Closing Date and (b) any material



                                       20
   22

failure of WEDGE to comply with or satisfy any covenant, condition or agreement
to be complied with or satisfied by it hereunder. CB&I shall give prompt notice
to WEDGE of (a) the existence or occurrence of each condition or state of facts
that will or reasonably could be expected to cause any representation or
warranty of CB&I contained herein to be untrue or inaccurate at or prior to the
Closing Date, (b) any material failure of CB&I to comply with or satisfy any
covenant, condition or agreement to be complied with or satisfied by it
hereunder and (c) CB&I's receipt of any Alternative Proposal, or any requests
for information or the initiation of discussions or negotiations from any third
party who states a desire to make or consider making any Alternative Proposal,
and CB&I shall include with such notice the identity of the person or group
initiating such discussions or negotiations, requesting such information or
making such Alternative Proposal, and the material terms and conditions of any
such Alternative Proposal (and any subsequent material modifications thereof).
The delivery of any notice pursuant to this Section 6.04 shall not be deemed to
(a) modify the representations or warranties herein of the party delivering that
notice, or any other party; (b) modify the conditions set forth or referred to
in Article VII; or (c) limit or otherwise affect the remedies available
hereunder to the party receiving that notice.

          Section 6.05 Fees and Expenses. In consideration of WEDGE and its
Affiliates entering into this Agreement and the Funding Agreement and taking
action to consummate the transactions contemplated hereby and thereby and
incurring the costs and expenses related thereto and other losses and expenses,
including the foregoing by WEDGE of other opportunities, WEDGE and CB&I agree
that CB&I shall pay to WEDGE $195,000 in cash within seven (7) days of the
Closing Date as a partial reimbursement of WEDGE's expenses. Except as provided
in the immediately preceding sentence or as otherwise specifically provided
elsewhere in this Agreement, WEDGE and CB&I shall bear their own fees and
expenses incurred in connection with this Agreement and in connection with all
obligations required to be performed by each of them under this Agreement.

          Section 6.06 Publicity. The parties hereto agree to consult with one
another prior to the issuance of any press release or public statement relating
to or concerning this Agreement or the matters contained herein. Such
consultation shall include prior notification of a party's intent to issue a
press release accompanied by a copy of the proposed language of such press
release or public statement. If CB&I or WEDGE is required to issue a press
release by law or a securities exchange, it shall use its best efforts to inform
the other party hereto prior to such issuance.

          Section 6.07 Commercially Reasonable Efforts. Each of WEDGE and CB&I
will use commercially reasonable efforts to take all actions and do all things
necessary in order to consummate and make effective the transactions
contemplated by this Agreement, including the satisfaction, but not the waiver,
of the closing conditions set forth in Article VII. If the Federal Trade
Commission or the Antitrust Division of the Department of Justice raises an
objection to the PDM Acquisition and the transactions contemplated hereby,
and/or proposes or seeks to impose any divestiture, operating restriction or
other condition, CB&I agrees, expeditiously and in good faith, to discuss such
objection, conditions and possible resolutions with such Governmental Authority.
Notwithstanding the foregoing, CB&I's Board of Supervisory Directors shall not
be required to take any action that it has determined in good faith, based on
the advice of outside counsel, would constitute a breach of its fiduciary duties
to CB&I's shareholders under applicable law.



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                                  ARTICLE VII

                     CONDITIONS TO CLOSING AND CONSUMMATION


          Section 7.01 Conditions to the Obligations of Each Party. The
obligation of each party hereto to take the actions contemplated to be taken by
that party at the Closing is subject to receipt of all Governmental Approvals
required to be obtained by WEDGE or CB&I in connection with the consummation of
the PDM Acquisition and the purchase and sale of the PDM Financing Shares on or
before the Closing Date.

          Section 7.02 Conditions to the Obligations of WEDGE. The obligations
of WEDGE with respect to actions to be taken by it at or before the Closing Date
and the actions to be taken on the Closing Date are subject to the satisfaction,
or the waiver by WEDGE pursuant to Section 11.03, on or before the Closing Date
of the following:

          (a) all of the representations and warranties of CB&I set forth in
Article V shall be true and correct as of the Closing Date as though made at
that date other than such changes and exceptions that (i) are contemplated by
this Agreement or (ii) could not reasonably be expected, individually or in the
aggregate, to have a Material Adverse Effect;

          (b) CB&I shall have delivered the documents described in Sections
3.04(a);

          (c) CB&I shall have made application for and received approval for
listing of the shares of CB&I Stock constituting the PDM Financing Shares on a
"when-issued" basis on the New York Stock Exchange, Inc.;

          (d) the PDM Acquisition shall have been consummated or there shall be
no conditions precedent to the consummation of the PDM Acquisition; and

          (e) all third-party, non-governmental consents or approvals necessary
for the consummation of the transactions contemplated by this Agreement shall
have been received.

          Section 7.03 Conditions to the Obligations of CB&I. The obligations of
CB&I with respect to actions to be taken by it at or before the Closing Date are
subject to the satisfaction, or the waiver by CB&I pursuant to Section 11.03, on
or before the Closing Date of the following:

          (a) all of the representations and warranties of WEDGE set forth in
Article IV shall be true and correct as of the Closing Date as though made at
that date other than such changes or exceptions that (i) are contemplated by
this Agreement or (ii) could not reasonably be expected, individually or in the
aggregate, to have a Material Adverse Effect;

          (b) WEDGE shall have delivered the documents described in Section
3.04(b);

          (c) the PDM Acquisition shall have been consummated or there shall be
no conditions precedent to the consummation of the PDM Acquisition; and

          (d) all third-party, non-governmental consents or approvals necessary
for the consummation of the transactions contemplated by this Agreement shall
have been received.



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                                  ARTICLE VIII

                         COVENANTS FOLLOWING THE CLOSING


          Section 8.01 Post-Closing Assistance. From and after the Closing Date,
upon the reasonable request of the CB&I or WEDGE, as the case may be, the
parties hereto shall do, execute, acknowledge and deliver all such further acts,
assurances, deeds, assignments, transfers, conveyances and other instruments and
papers as may be reasonably required or appropriate to carry out the
transactions contemplated by this Agreement.

          Section 8.02 No Transactions. For a period of six months following the
Closing Date, CB&I will use its best efforts, consistent with the fiduciary
duties of the Supervisory Board, not to enter into any Business Combination,
Recapitalization or other corporate transaction that would subject WEDGE to any
liability pursuant to the Securities Exchange Act of 1934, as amended, or the
rules promulgated thereunder by the Commission, including pursuant to Section
16, including the forfeiture of any "profit" pursuant to Section 16(b) thereof.
As of the date hereof, CB&I does not contemplate, plan, expect or anticipate
entering into any such transaction.

                                   ARTICLE IX

                   SURVIVAL OF REPRESENTATIONS AND WARRANTIES


          Section 9.01 Survival of Representations and Warranties.

          (a) Except as set forth below in Sections 9.01(b) and (c), the
representations and warranties contained in Articles IV and V will terminate and
expire 12 months after the Closing Date.

          (b) The representations and warranties set forth in or deemed to be
set forth in Section 5.08 and Section 5.14 will terminate and expire five years
after discovery of the condition, circumstance or fact constituting a breach of
any such representation or warranty.

          (c) The representations and warranties set forth in or deemed to be
set forth in Section 4.01, Section 4.02, Section 4.03, Section 4.04, Section
5.01, Section 5.02, Section 5.05, Section 5.06, Section 5.07, Section 5.17 and
Section 5.19 will survive the Closing and Effective Time indefinitely.

                                   ARTICLE X

                             [INTENTIONALLY OMITTED]
                                   ARTICLE XI

                               GENERAL PROVISIONS


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          Section 11.01 Treatment of Confidential Information. (a) Each of the
parties to this Agreement acknowledge that they have or may have had in the
past, currently have and in the future may have access to Confidential
Information of the other party. Each of the parties agrees that it will keep
confidential all such Confidential Information furnished to it and, except with
the specific prior written consent of the other party, will not disclose such
Confidential Information to any Person, except (i) Representatives of the
parties and (ii) its own Representatives, provided that these Representatives
(other than counsel) agree to the confidentiality provisions of this Section
11.01; provided, however, that Confidential Information shall not include such
information as (i) becomes known to the public generally through no fault of any
party, (ii) is required to be disclosed by law or the order of any Governmental
Authority under color of law, or (iii) the disclosing party reasonably believes
is required to be disclosed in connection with the defense of a lawsuit against
the disclosing party.

          (b) The obligations of the parties under this Section 11.01 shall
survive the termination of this Agreement.

          Section 11.02 Assignment; No Third-Party Beneficiaries. This Agreement
and the rights of the parties hereunder may not be assigned (except by operation
of law) and shall be binding on and inure to the benefit of the parties hereto,
the successors of CB&I, and the successors of WEDGE. Neither this Agreement nor
any other Transaction Document is intended, or shall be construed, deemed or
interpreted, to confer on any Person not a party hereto or thereto any rights or
remedies hereunder or thereunder, except as otherwise provided expressly herein
or therein.

          Section 11.03 Entire Agreement; Amendment; Waivers. This Agreement and
the documents delivered pursuant hereto constitute the entire agreement and
understanding among WEDGE and CB&I with regard to the purchase and sale of the
PDM Financing Shares and supersede all prior agreements and understandings, both
written and oral, relating to the subject matter of this Agreement. This
Agreement may be amended, modified or supplemented, and any right hereunder may
be waived, if, but only if, that amendment, modification, supplement or waiver
is in writing and signed by WEDGE and CB&I. The waiver of any of the terms and
conditions hereof shall not be construed or interpreted as, or deemed to be, a
waiver of any other term or condition hereof.

          Section 11.04 Notices. All notices required or permitted hereunder
shall be in writing, and shall be deemed to be delivered and received (a) if
personally delivered or if delivered by telex, telegram, facsimile or courier
service, when actually received by the party to whom notice is sent or (b) if
delivered by mail (whether actually received or not), at the close of business
on the third business day next following the day when placed in the mail,
postage prepaid, certified or registered, addressed to the appropriate party or
parties, at the address of such party set forth below (or at such other address
as such party may designate by written notice to all other parties in accordance
herewith):


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          (1)     if to CB&I, addressed to it at:

                  Chicago Bridge & Iron Company N.V.
                  c/o Chicago Bridge & Iron Company
                  1501 North Division Street
                  Plainfield, Illinois 60544
                  Attn:  Secretary
                  Fax:  (815) 439-6297

          with a copy to:

                  Winston & Strawn
                  35 Wacker Drive
                  Chicago, Illinois 60601
                  Attn:  James Reum
                  Fax:  (312) 558-5700

          and

          (2)     if to WEDGE, addressed to it at:
                  Farinvest, Ltd.
                  Ugland House
                  South Church Street
                  Grand Cayman, Cayman Islands B.W.I.
                  Attn:  Managing Director
                  Fax:  011-31-20-647-2212

          with a copy to:

                  WEDGE Group Incorporated
                  1415 Louisiana, Suite 3000
                  Houston, Texas  77002
                  Attn:  General Counsel
                  Fax:  (713) 524-3586

          Section 11.05 GOVERNING LAW, JURISDICTION AND VENUE. THIS AGREEMENT
AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HERETO SHALL BE GOVERNED BY AND
CONSTRUED AND ENFORCED IN ACCORDANCE WITH THE SUBSTANTIVE LAWS OF THE STATE OF
NEW YORK. WEDGE AND CB&I EACH HEREBY IRREVOCABLY AGREE THAT VENUE OF ANY LEGAL
PROCEEDINGS OR ARBITRATION ARISING OUT OF OR RELATING TO THIS AGREEMENT SHALL BE
IN NEW YORK CITY.

          Section 11.06 WAIVER OF CERTAIN CLAIMS. (A) NEITHER WEDGE NOR CB&I
SHALL BE ENTITLED TO RECOVER FROM THE OTHER ANY LOSSES, COSTS, EXPENSES, OR
DAMAGES ARISING UNDER THIS AGREEMENT OR IN CONNECTION WITH OR WITH RESPECT TO
THE TRANSACTIONS CONTEMPLATED IN THIS



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AGREEMENT IN ANY AMOUNT IN EXCESS OF THE ACTUAL COMPENSATORY DAMAGES, COURT OR
ARBITRATION COSTS AND REASONABLE ATTORNEY FEES AND EXPENSES SUFFERED BY SUCH
PARTY, AND (B) WEDGE AND CB&I HEREBY IRREVOCABLY WAIVE ANY AND ALL RIGHTS TO
ASSERT ANY CLAIM FOR INDIRECT, CONSEQUENTIAL, SPECIAL, EXEMPLARY OR PUNITIVE
DAMAGES ARISING IN CONNECTION WITH OR WITH RESPECT TO THE TRANSACTIONS
CONTEMPLATED IN THIS AGREEMENT.

          Section 11.07 Exercise of Rights and Remedies. Except as otherwise
provided herein, no delay or omission in the exercise of any right, power or
remedy accruing to any party hereto as a result of any breach or default
hereunder by any other party hereto shall impair any such right, power or
remedy, nor shall it be construed, deemed or interpreted as a waiver of or
acquiescence in any such breach or default, or of any similar breach or default
occurring later; nor shall any waiver of any single breach or default be
construed, deemed or interpreted as a waiver of any other breach or default
hereunder occurring before or after that waiver.

          Section 11.08 Reformation and Severability. If any provision of this
Agreement is invalid, illegal or unenforceable, that provision shall, to the
extent possible, be modified in such manner as to be valid, legal and
enforceable but so as to most nearly retain the intent of the parties hereto as
expressed herein, and if such a modification is not possible, that provision
shall be severed from this Agreement, and in either case the validity, legality
and enforceability of the remaining provisions of this Agreement shall not in
any way be affected or impaired thereby.

          Section 11.09 Incorporation of Exhibits and Schedules. The Exhibits
and Schedules identified in this Agreement are incorporated herein by reference
and made a part hereof. Information disclosed on a certain Schedule shall be
deemed as disclosed on any other Schedule to which such information may also
relate.

          Section 11.10 Counterparts. This Agreement may be executed in two or
more counterparts, each of which shall be deemed an original but all of which
together shall constitute one and the same instrument.

                                  ARTICLE XII

                                   TERMINATION


          Section 12.01 Termination of this Agreement. This Agreement may be
terminated:

          (a) by the mutual written consent duly authorized by the Supervisory
Board of Directors of CB&I and the Managing Director of WEDGE and by the
management board of CB&I;

          (b) by CB&I or WEDGE at any time after February 15, 2001, if at the
time notice of such termination is given, the transactions contemplated by this
Agreement have not been consummated;



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          (c) by CB&I or WEDGE if, on the Closing Date, a preliminary or
permanent injunction has been entered restraining, prohibiting or declaring
illegal the sale of the PDM Financing Shares by CB&I or the purchase of the PDM
Financing Shares by WEDGE, and immediately upon any such termination CB&I shall
pay the fees and expenses contemplated by Section 6.05; and

          (d) by WEDGE, if the CB&I Supervisory Board of Directors shall have
failed to recommend, or shall have withdrawn, its approval or recommendation of
the transactions contemplated by this Agreement, or shall have recommended
acceptance of any Alternative Proposal.

          Section 12.02 Effect of Termination. In the event of the termination
of this Agreement pursuant to Section 12.01, this Agreement shall forthwith
become void and have no effect, without any liability on the part of any party
or its directors, officers or stockholders, except that (i) the provisions of
this Section 12.02, Section 11.01 and Section 6.05 shall survive any such
termination and (ii) except as provided in Section 6.05, all costs and expenses
incurred in connection with the transactions contemplated by this Agreement
shall be paid by the party incurring such expenses. Nothing contained in this
Section 12.02 shall relieve any party from its liability for any breach of this
Agreement.

                            [signature page follows]









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          IN WITNESS WHEREOF, the undersigned parties have executed this
Agreement as of the date first written above.


                                        FARINVEST, LTD.

                                             BY:  ISSAM M. FARES,
                                             ITS MANAGING DIRECTOR

                                             By:  /s/ Richard E. Blohm, Jr.
                                             Name:  Richard E. Blohm, Jr.
                                             Title: Attorney-in-Fact






                                        CHICAGO BRIDGE & IRON COMPANY N.V.


                                        BY:  CHICAGO BRIDGE & IRON
                                             COMPANY B.V., ITS MANAGING DIRECTOR


                                        By:  /s/ Gerald M. Glenn
                                             -------------------

                                        Title:  Managing Director
                                                --------------------------------





                  [SIGNATURE PAGE TO STOCK PURCHASE AGREEMENT]





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