<PAGE>
 
================================================================================
                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549

                                   FORM 10-K

(Mark One)

       [X]  ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
            SECURITIES EXCHANGE ACT OF 1934
            For the fiscal year ended December 31, 1996

                                      OR

       [ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
            SECURITIES EXCHANGE ACT OF 1934
            For the transition period from          to        

                         Commission file number 1-5259

                             PITT-DES MOINES, INC.
            (Exact name of registrant as specified in its charter)

               Pennsylvania                             25-0729430
      (State or other jurisdiction of                (I.R.S. Employer
      incorporation or organization)                Identification No.)

3400 Grand Avenue, Pittsburgh, Pennsylvania                15225
 (Address of principal executive offices)               (Zip Code)


                                 412-331-3000
             (Registrant's telephone number, including area code)

          Securities Registered Pursuant to Section 12(b) of the Act:

Title of each class                    Name of each exchange on which registered
-------------------                    -----------------------------------------
Common Stock, no par value                               American Stock Exchange


       Securities Registered Pursuant to Section 12(g) of the Act: None

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was 
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.   Yes  X   No     
                                        -----   -----

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 
of Regulation S-K is not contained herein, and will not be contained, to the 
best of  registrant's knowledge, in definitive proxy or information statements 
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K [  ].

The aggregate market value of the registrant's voting stock held by 
non-affiliates was at least $53,987,963 on February 28, 1997, based upon the 
average between the highest and lowest sales prices of the registrant's Common 
Stock as reported in the consolidated transactions reporting system.

<TABLE> 
<S>                                                                                  <C> 
    Common Stock outstanding as of February 28, 1997.................................2,322,001 shares.
</TABLE> 

Documents Incorporated By Reference:

    Certain portions of the documents of the Registrant listed below have been 
incorporated by reference into the indicated parts of this Annual Report on Form
10-K:

<TABLE> 
<S>                                                                                  <C> 
    Proxy Statement anticipated to be dated March 31, 1997...........................Part III, Items 10-13

    Annual Report to Stockholders for fiscal year ended December 31, 1996............Part I and Part II
</TABLE> 

================================================================================
<PAGE>
 
                                    PART I

Item 1.  Business

General

  Pitt-Des Moines, Inc. and its subsidiaries (PDM or the Company) began
conducting business in 1892 and was incorporated in Pennsylvania on February 14,
1916.  The Company's principal executive offices are located at 3400 Grand
Avenue, Pittsburgh, Pennsylvania  15225, telephone number (412) 331-3000.

  Effective with the disposition of CVI's operations during the fourth quarter
of 1994 (see Discontinued Operation note accompanying the consolidated financial
statements), the Company is comprised of three business segments:  Engineered
Construction Division, Steel Construction and Steel Service Centers.  Each
segment is a profit center except the Steel Construction business segment which
is divided into individual profit centers as noted below.

  A summary of the Company's products and services by business segment is set
forth below.

  Engineered Construction Division

  In 1994, the Engineered Construction Division was reorganized into three
  project groups: Water, Industrial, and International and Technology. These
  market groups provide:

  a) The capability to design, fabricate and erect many types of facilities and
     structures; services offered include research and design, material
     selection, preparation of detailed drawings, shop fabrication, field
     erection and subcontract management.

  b) The capability to design, fabricate and erect elevated and flat bottom
     water storage tanks for water service and fire protection requirements and
     treatment tanks for the purification, filtration and softening of water.
     The principal purchasers of the Company's water storage tanks and
     wastewater treatment facilities are government agencies and private
     industry.

  c) The capability to design, fabricate and erect oil and chemical storage
     tanks used for storing crude oil, petroleum, gasoline and other petroleum
     derivatives and chemicals. The Company has developed and patented certain
     systems, parts and sealing devices which help to reduce the hazards of fire
     and explosion from the stored products, as well as to decrease air
     pollution and vapor loss. Additionally, the Company fabricates and erects
     various vessels used in the processing of a variety of oil and chemical
     products. The oil and chemical tanks, sealing devices and process vessels
     are produced principally for the petroleum, petrochemical, chemical and
     food processing industries as well as government agencies.

                                      -2-
<PAGE>
 
Item 1.  Business (Cont'd)

  d) The capability to fabricate and erect miscellaneous plate work which
     includes penstocks and breechings, stacks and stack liners, scrubbers,
     absorbers, flow conductors and heat exchangers for utilities and private
     industry.

  e) The capability to design, fabricate and erect high speed wind tunnels,
     altitude test chambers, hydrospace test facilities and high vacuum and
     thermal test facilities for use in connection with energy, aerospace and
     defense research.

  f) The capability to design and build supercritical fluid extraction
     facilities for the food processing industry.

  g) The capability to design and build anaerobic digesters for the wastewater
     treatment industry.


  Steel Construction

  On September 1, 1994, the Company acquired the bridge fabricating assets of
  Phoenix Steel, Inc., located in Eau Claire, Wisconsin. These assets were
  combined with the bridge fabricating assets of Hartwig Mfg. Corp. (which was
  merged with and into the Company on December 31, 1994) to form the PDM Bridge
  Division. On February 17, 1997, the Company announced plans to begin
  construction of a new structural steel fabricating facility located in the
  southwestern part of the United States. This new facility is expected to be
  operational in the third quarter of 1997. Along with this plan, the Company
  announced the decision to close the Chicago Steel Construction facility
  located in Melrose Park, Illinois. Certain employees and equipment from the
  Melrose Park facility are expected to be redeployed to both the new facility
  as well as existing bridge fabricating plants in Wisconsin. On March 10, 1997,
  the Company acquired Candraft Detailing, Inc., an engineering drafting company
  serving the steel building and bridge fabrication industry, located in
  Vancouver, British Columbia. This acquisition is expected to enhance the
  drafting capabilities of the Steel Construction business segment. The Steel
  Construction business segment will continue to provide:

  a) The capability to fabricate and erect structural steel for commercial,
     institutional and public sector buildings for government agencies, private
     developers and general contractors.

  b) The capability to fabricate structural steel for new bridges and fabricate
     and erect structural steel for bridge rehabilitation for government
     agencies and general contractors.

                                      -3-
<PAGE>
 
Item 1.  Business (Cont'd)

  Steel Service Centers

  The Steel Service Centers operate seven steel service centers and three
  culvert facilities located in the West and Midwest regions of the United
  States. On January 31, 1997, the Company acquired 90% of the stock of General
  Steel Corporation, a steel service center facility, located in Vancouver,
  Washington. This acquisition will expand this segments market area into the
  Pacific Northwest. The Steel Service Centers process and distribute to the end
  users, a general line of carbon steel products including plates, sheets,
  structural shapes, bars, tubes, pipe and other miscellaneous metal products.
  This Division also manufactures and markets to the end users, corrugated metal
  culvert pipe and accessories. The Steel Service Centers' primary markets
  include steel fabricators, original equipment manufacturers and the mining,
  logging, agricultural and road construction industries.

  The Company and the industry as a whole deem the maintenance of adequate
  levels of inventory to be integral to the Service Center business. The Company
  believes that it has adequate levels of inventory on hand to meet current and
  anticipated customer demand.

Other

  Several large companies compete nationally in some product lines with the
Company and there are several local and regional companies that compete in
certain product lines in specific geographic areas.  The majority of the
Company's business is secured through open competitive bidding or through direct
negotiations with industry or government agencies. Competition is based
primarily on performance including the ability to provide design, engineering
and on-site field construction services in a cost-effective, timely manner.  The
Steel Service Centers' volume of business is based on the price, delivery and
credit terms, and first stage preprocessing operations, offered to its customers
as well as its reputation.

  Earned revenue was $468 million in 1996, compared with $461 million in 1995
and $408 million in 1994.  For further financial information refer to
Consolidated Financial Statements in PDM's 1996 Annual Report to Stockholders
and incorporated herein by reference.

  The principal raw materials essential to the Company's business are steel,
alloys and other metal plates and structural sections.  The Company procures
these raw materials from various domestic and foreign sources including, the
mills of USX Corporation, Bethlehem Steel Corporation, Northwestern Steel and
Wire Company, Nucor Steel, British Steel and Mitsubishi International
Corporation.

  The Company has a license and technical assistance agreement with Roediger, a
German corporation, which gives the Company exclusive rights in North America
and other selected countries worldwide to use the Roediger technology, a process
which utilizes anaerobic digestion in the treatment of wastewater.  Revenues to
date from this technology have not been material to the Company.

                                      -4-
<PAGE>
 
Item 1.  Business (Cont'd)

  Some components of the other products made and erection techniques used by the
Company are covered by patents owned or licensed by the Company.  None of these
are deemed to be material to the Company from an overall financial viewpoint.

  The Company had a backlog of uncompleted contracts of $172 million on December
31, 1996 compared to $183 million on December 31, 1995.  Substantially all
backlog is expected to be completed during 1997.

  Factors such as the type and scope of operations in progress at any given
time, including weather conditions at field sites, create fluctuations in the
employment level at PDM.  On December 31, 1996, the Company employed 2,006
persons, of which 649 were salaried personnel and 1,357 were hourly personnel.

  The financial information for business segments is included in the Business
Segment Information section in PDM's 1996 Annual Report to stockholders, which
section is incorporated herein by reference.

Item 2.  Properties

  Operations of the Company are conducted at both owned and leased properties.
In addition, certain owned properties of the Company are leased to third party
tenants.  The following table indicates each of the Company's facilities in the
United States by:  segment, location, type of facility, year operations began,
and square footage of property owned or leased on December 31, 1996:

<TABLE>
<CAPTION>
                                                                     YEAR
                                              TYPE OF             OPERATIONS     SQUARE
LOCATION                                     FACILITY               BEGAN        FOOTAGE
<S>                                 <C>                           <C>            <C>
Engineered Construction Division                                         
                                                                         
Harpersville, Alabama (1)               Warehouse and office        1994          11,500
Fresno, California                           Toolhouse              1963          52,140
Clive, Iowa                         Fabrication plant and office    1955         176,540
Des Moines, Iowa                             Toolhouse              1900          29,000
Pittsburgh, Pennsylvania                Office and toolhouse        1908          98,780
Warren, Pennsylvania                     Fabrication plant          1959         125,960
Franklin, Tennessee                          Toolhouse              1977          28,220
Hitchcock, Texas (2)                         Toolhouse              1994           5,000
The Woodlands, Texas (3)                       Office               1996          19,300
Provo, Utah                              Fabrication plant          1959         154,950
 
</TABLE>

                                      -5-
<PAGE>
 
Item 2.  Properties (Cont'd)
 
<TABLE>
<CAPTION>
                                                                     YEAR
                                              TYPE OF             OPERATIONS     SQUARE
LOCATION                                     FACILITY               BEGAN        FOOTAGE
<S>                                 <C>                           <C>            <C>
Steel Construction
 
Stockton, California                Fabrication plant and office    1987         143,000
Chicago, Illinois                   Fabrication plant and office    1987         520,800
Eau Claire, Wisconsin               Fabrication plant and office    1994         309,500
Wausau, Wisconsin                   Fabrication plant and office    1991         157,000
Port Coquitlam, B.C. Canada (4)                Office               1997          12,300
 
Steel Service Centers
 
Fresno, California                      Warehouse and office        1955         112,800
Santa Clara, California                 Warehouse and office        1947         108,530
Stockton, California                    Warehouse and office        1955         191,500
Cedar Rapids, Iowa                      Warehouse and office        1976          66,800
Sparks, Nevada                          Warehouse and office        1974          78,940
Tualatin, Oregon                        Warehouse and office        1964          31,620
Spanish Fork, Utah                      Warehouse and office        1977          74,280
Arlington, Washington (5)               Warehouse and office        1993          13,970
Vancouver, Washington (6)               Warehouse and office        1997         138,600
 
Idle Holdings, Including Plant and Property (7)
 
Sacramento, California                          Land                1966              --
Des Moines, Iowa                    Fabrication plant and office    1900         339,100
Hilliard, Ohio                      Fabrication plant and office    1971         179,000
Pittsburgh, Pennsylvania                       Office               1908          10,234
Provo, Utah (8)                                Office               1959          15,731
----------
</TABLE>
(1) Company leases land and building from outside third party with an option
    to purchase.  Lease will expire January 31, 2001.
(2) Company leases land and building from outside third party.  Lease will
    expire July 1, 1997.
(3) Company leases building from outside third party.  Lease will expire August
    31, 2006.
(4) Company leases building from outside third party.  Lease will expire
    November 30, 2002.
(5) Company leases land from outside third party.  Lease will expire January
    31, 2003.
(6) Company leases land and building from outside third party.  Lease will
    expire September 1, 1999.
(7) Company pursues the sale or development of all idle facilities and
    regularly evaluates similar opportunities for facilities not fully
     utilized.
(8) Company is leasing facility to outside third party.  Lease will expire
    January 31, 1998.

                                      -6-
<PAGE>
 
Item 2.  Properties (Cont'd)

  The properties listed above are utilized by the Company's business segments as
indicated. The Company's production capacity is adequate for its present needs.
The Company believes that its properties have been adequately maintained, are
generally in good condition and are suitable for the Company's business as now
conducted.

Item 3.  Legal Proceedings

  See Contingencies note accompanying the consolidated financial statements in
PDM's 1996 Annual Report to Stockholders, which note is incorporated herein by
reference.

  On May 14, 1996 the Company filed an action in the United States District 
Court for the Northern District of Illinois (Eastern Division) captioned 
PITT-DES MOINES, INC. V. METROPOLITAN PIER & EXPOSITION AUTHORITY ET AL.,
seeking reimbursement in excess of $15.0 million for additional work and making
other claims in connection with this matter. On June 4, 1996, certain of the
defendants in said action made counterclaims against the Company in amounts
approximating $3.5 million. While counsel believes that the Company has a basis
for the claim, neither management nor counsel is able to predict with certainty
the ultimate resolution of this matter. As additional information becomes
available, the Company may revise its estimate of potential recovery, which
could result in a material adjustment to the results of operations in future
periods.

Item 4.  Submission of Matters to a Vote of Security Holders

  Not applicable

Executive Officers of the Registrant

  Information regarding executive officers of the Registrant is presented in
Part III following and incorporated herein by reference.

                                      -7-
<PAGE>
 
                                    PART II


Information for Items 5, 6 and 7 is included in PDM's 1996 Annual Report to
Stockholders and is incorporated herein by reference (and except for these
sections, and sections incorporated herein by reference in Items 1 and 8 of this
report, PDM's Annual Report to Stockholders is not deemed to be filed as part of
this report):

<TABLE>
<CAPTION>
                                                           ANNUAL REPORT
                                                           TO STOCKHOLDERS
ITEM NO.    TITLE                                          SECTION/TITLE
--------------------------------------------------------------------------------------------------------------------
<S>         <C>                                            <C>
 
Item 5.     Market for Registrant's Common Equity          Common Stock Information
            and Related Stockholder Matters                included in Stockholders'
                                                           Reference section
 
Item 6.     Selected Financial Data                        Five-Year Selected
                                                           Financial Data
 
Item 7.     Management's Discussion and Analysis           Management's Discussion
            of Financial Condition and Results of          and Analysis
            Operations

Item 8.      Financial Statements and Supplemental Data
</TABLE> 

The financial statements consisting of Consolidated Statements of Income,
Consolidated Statements of Financial Condition, Consolidated Statements of Cash
Flows, Consolidated Statements of Stockholders' Equity, Notes to Consolidated
Financial Statements, and Business Segment Information are included in the
Consolidated Financial Statements section of PDM's 1996 Annual Report to
Stockholders, which are incorporated herein by reference.  The report of
independent auditors on PDM's consolidated financial statements is in the Report
of Independent Auditors and Management section of PDM's 1996 Annual Report to
Stockholders which is incorporated herein by reference.

The unaudited Two-Year Quarterly Results of Operations in PDM's 1996 Annual
Report to Stockholders is incorporated herein by reference.

Item 9.     Changes in and Disagreements With Accountants on Accounting and
Financial Disclosure

  Not applicable

                                      -8-
<PAGE>
 
                                    PART III

Item 10.  Directors and Executive Officers of the Registrant (1)

  Regarding the directors of the Registrant, reference is made to the
information set forth under the caption "Election of Directors" in the Company's
definitive Proxy Statement anticipated to be dated March 31, 1997 (Proxy
Statement) which information is incorporated herein by reference.

  The principal executive officers of the Company and their recent business
experience are as follows:

W. R. Jackson, age 88

  Director since 1940;
  Chairman Emeritus since 1988; formerly Chairman of the Board since 1971.
  Mr. Jackson has been with the Company since 1936.

P. O. Elbert, age 66

  Director since 1988;
  Chairman of the Board of the Company since 1990; formerly President of the
  Company since 1988 and President, PDM Structural Group since 1987. Mr. Elbert
  joined the Company in 1987. Prior to 1987, Mr. Elbert was Vice Chairman of
  Chicago Steel Corporation since 1986; formerly a partner of Elbert and McKee
  Company since 1984; formerly President and Chief Executive Officer of Flint
  Steel Corporation since 1979; and formerly Group Vice President of Inryco,
  Inc., a subsidiary of Inland Steel Company since 1969.

Wm. W. McKee, age 58 (2)

  Director since 1988;
  President and Chief Executive Officer of the Company since 1990; formerly
  President, PDM Plate Group since May 1987 and formerly Executive Vice
  President, PDM Structural Group since April 1987. Mr. McKee joined the Company
  in 1987. Prior to 1987, Mr. McKee was Secretary of Chicago Steel Corporation
  since 1986; formerly a partner of Elbert and McKee Company since 1984;
  formerly a consultant with McKee and Associates since 1983; formerly President
  of Hogan Manufacturing since 1980; and formerly President of Herrick
  Corporation since 1973.

R. A. Byers, age 49 (2)

  Treasurer since 1988 and Vice President, Finance and Administration since
  1987; formerly Vice President, Finance since 1984; formerly Controller since
  1982; formerly Assistant Controller since 1981; formerly Manager of Financial
  Reporting since 1979; and formerly with Ernst & Young LLP for ten years.

                                      -9-
<PAGE>
 
Item 10.  Directors and Executive Officers of the Registrant (Cont'd)

T. R. Lloyd, age 48 (2)

  Secretary and General Counsel since 1990; formerly Senior Attorney of Buchanan
  Ingersoll Professional Corporation, since 1989; formerly Vice President,
  Secretary and General Counsel for Arch Mineral Corporation since 1984; and
  formerly Director and Secretary of U.S. Steel Mining Co., Inc. since 1979.

____________________
(1)  Except where otherwise indicated, all references are to positions held with
     Pitt-Des Moines, Inc.  Each executive officer of the Company is elected
     annually by the Board of Directors until his successor is elected and
     qualified, and each has served continually as an officer since first
     elected.

(2)  The Company has agreements with each of Messrs. McKee, Byers and Lloyd
     covering, among other things, their positions as executive officers of the
     Company after a change of control.

Regarding Section 16 compliance, reference is made to the information set forth
under the caption "Compliance with Section 16 of the Exchange Act" in the
Company's definitive Proxy Statement anticipated to be dated March 31, 1997
which information is incorporated herein by reference.

Item 11.  Executive Compensation

  Reference is made to the information set forth under the captions "Board of
Directors and Committees of the Board," "Executive Compensation and Other
Information," "Compensation Committee Interlocks and Insider Participation"
appearing in the Company's Proxy Statement, which information is incorporated
herein by reference; provided, however, that the information set forth under the
captions "Compensation Committee Report on Executive Compensation" and
"Performance Graph" in the proxy Statement shall not be deemed to be soliciting
material or to be "filed" with the Commission or subject to Regulation 14A or
14C (other than as provided in Item 402 of Regulation S-K) or to the liabilities
of Section 18 of the Securities Exchange Act of 1934, as amended.

Item 12.  Security Ownership of Certain Beneficial Owners and Management

  Reference is made to the information contained under the captions
"Stockholdings of Management" and "Principal Holders of Common Stock" in the
Company's Proxy Statement which information is incorporated herein by reference.

Item 13.  Certain Relationships and Related Transactions

  Reference is made to the information contained under the caption "Compensation
Committee Interlocks and Insider Participation" in the Company's Proxy Statement
which information is incorporated herein by reference.

                                      -10-
<PAGE>
 
                                    PART IV

Item 14. Exhibits, Financial Statement Schedules and Reports on Form 8-K

(a) 1.     Financial Statements
         
           The following consolidated financial statements and Report of
           Independent Auditors previously incorporated by reference in Part II,
           Item 8 of this report are incorporated herein by reference:
           
           Report of Independent Auditors
         
           Consolidated Statements of Income -- Years Ended December 31, 1996,
           1995 and 1994
         
           Consolidated Statements of Financial Condition as of December 31,
           1996 and 1995
         
           Consolidated Statements of Cash Flows -- Years Ended December 31,
           1996, 1995 and 1994
           
           Consolidated Statements of Stockholders' Equity -- Years Ended
           December 31, 1996, 1995 and 1994
         
           Notes To Consolidated Financial Statements
         
    2.     Financial Statement Schedules
         
           The following consolidated financial statement schedule of Pitt-Des
           Moines, Inc. and subsidiaries is included in Item 14(d):
         
           Schedule II. Valuation and Qualifying Accounts for years ended
           December 31, 1996, 1995 and 1994
         
           All other schedules are omitted because they are not applicable or
           the required information is shown in the consolidated financial
           statements or notes thereto.
         
    3.     Exhibits:
         
    3.1    Articles of Incorporation, as amended to date (filed as Exhibit 3.1
           to the Company's quarterly report on Form 10-Q for the quarter ended
           September 30, 1989 and incorporated herein by reference)
         
    3.2    Bylaws, as amended to date (filed as Exhibit 3.2 to the Company's
           quarterly report on Form 10-Q for the quarter ended September 30,
           1989 and incorporated herein by reference)

                                      -11-
<PAGE>
 
Item 14.  Exhibits, Financial Statement Schedules and Reports on form 8-K
(Cont'd)

    4.1    Amended and Restated Credit Agreement dated as of June 30, 1992 by
           and among Pitt-Des Moines, Inc. and Pittsburgh National Bank, Wells
           Fargo Bank, N.A. and American National Bank (filed as Exhibit 4.1 to
           the Company's annual report on Form 10-K for the year ended December
           31, 1992 and incorporated herein by reference)
         
    4.2    First Amendment dated November 23, 1992 to Credit Agreement filed as
           Exhibit 4.1 hereto (filed as Exhibit 4.2 to the Company's annual
           report on Form 10-K for the year ended December 31, 1992 and
           incorporated herein by reference)
         
    4.3    Second Amendment dated June 10, 1993 to Credit Agreement filed as
           Exhibit 4.1 hereto (filed as Exhibit 4.1 to the Company's quarterly
           report on Form 10-Q for the quarter ended June 30, 1992 and
           incorporated herein by reference)
         
    4.4    Third Amendment dated December 16, 1993 to Credit Agreement filed as
           Exhibit 4.1 hereto (filed as Exhibit 4.2 to the Company's annual
           report on Form 10-K for the year ended December 31, 1993 and
           incorporated herein by reference)
         
    4.5    Fourth Amendment dated June 14, 1994 to Credit Agreement filed as
           Exhibit 4.1 hereto (filed as Exhibit 4.1 to the Company's quarter
           report on Form 10-Q for the quarter ended June 30, 1994 and
           incorporated herein by reference)
         
    4.6    Fifth Amendment dated December 8, 1994 to Credit Agreement filed as
           Exhibit 4.1 hereto (filed as Exhibit 4.6 to the Company's Annual
           Report on Form 10-K for the year ended December 31, 1994 and
           incorporated herein by reference)
         
    4.7    Sixth Amendment dated May 31, 1995 to Credit Agreement filed as
           Exhibit 4.1 hereto (filed as Exhibit 4.1 to the Company's quarterly
           report On form 10-Q for the quarter ended June 30, 1995 and
           incorporated herein by reference)
         
    4.8    Seventh Amendment dated June 30, 1996 to Credit Agreement filed as
           Exhibit 4.1 hereto (filed as Exhibit 4.1 to the Company's quarterly
           report on Form 10-Q for the quarter ended June 30, 1996 and
           incorporated herein by reference)
         
    10.1*  Agreement executed by and between the Company and Wm. W. McKee (filed
           as Exhibit 10.1 to the Company's annual report on Form 10-K for the
           year ended December 31, 1990 and incorporated herein by reference)
         
    10.2*  Agreement executed by and between the Company and R. A. Byers (filed
           as Exhibit 10.1 to the Company's quarterly report on Form 10-Q for
           the quarter ended June 30, 1991 and incorporated herein by reference)

                                      -12-
<PAGE>
 
Item 14.  Exhibits, Financial Statement Schedules and Reports on form 8-K
(Cont'd)

    10.3*  Agreement executed by and between the Company and T. R. Lloyd (filed
           as Exhibit 10.2 to the Company's quarterly report on Form 10-Q for
           the quarter ended June 30, 1991 and incorporated herein by reference)

    10.4*  Management Incentive Plan (filed as Exhibit 10.5 to the Company's
           annual report on Form 10-K for the year ended December 31, 1992 and
           incorporated herein by reference)

    10.5*  Summary of Company 1996 Management Incentive Plan (MIP) (filed
           herewith)

    10.6*  Retirement Plan for PDM Outside Directors as amended, effective May
           26, 1994 (filed as Exhibit 10.7 to the Company's annual report on
           Form 10-K for the year ended December 31, 1994 and incorporated
           herein by reference)

    10.7*  Retirement Plan for PDM Outside Directors as amended on September 14,
           1995, effective May 26, 1994 (filed as Exhibit 10.7 to the Company's
           annual report on Form 10-K for the year ended December 31, 1995 and
           incorporated herein by reference)

    10.8*  Stock Option Plan of 1990 (filed as Exhibit 4.01 to the Company's
           Registration Statement No. 33-34787 on Form S-8 filed May 7, 1990 and
           incorporated herein by reference)

    10.9*  Investment Letter and Registration Rights Agreement dated September
           21, 1993 by and between Pitt-Des Moines, Inc. and William W. McKee,
           Jr. (filed as Exhibit 10.1 to the Company's quarterly report on Form
           10-Q for the quarter ended September 30, 1993 and incorporated herein
           by reference)

    10.10* Investment Letter and Registration Rights Agreement dated September
           21, 1993 by and between Pitt-Des Moines, Inc. and Phillip O. Elbert
           (filed as Exhibit 10.2 to the Company's quarterly report on Form 10-Q
           for the quarter ended September 30, 1993 and incorporated herein by
           reference)

    10.11* Directors Stock Plan (filed under the Company's Registration
           Statement No. 333-13043 on Form S-8 dated September 30, 1996 and
           incorporated herein by reference)

    10.12* Stock Option Agreement executed by and between the Company and P.O.
           Elbert (filed herewith)

    11     Computation of Per Share Earnings (filed herewith)

    13     Those portions of the Annual Report to Stockholders for fiscal year
           ended December 31, 1996, which are incorporated herein by reference
           (filed herewith)

                                      -13-
<PAGE>
 
Item 14.  Exhibits, Financial Statement Schedules and Reports on Form 8-K
(Cont'd)

    21     Subsidiaries of Pitt-Des Moines, Inc. (filed herewith)

    23     Consent of Independent Auditors, Ernst & Young LLP (filed herewith)

    27     Financial Data Schedule

 
(b) Reports on Form 8-K:

    There were no reports on Form 8-K filed during the quarter ended December
    31, 1996.

------------------------
* Denotes management contract or compensatory plan or arrangement.

                                      -14-
<PAGE>
 
                                   Signatures

  Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange
Act of 1934, the registrant has duly caused this report to be signed on its
behalf by the undersigned, thereunto duly authorized.

                             PITT-DES MOINES, INC.


March 26, 1997                                    By: /s/   Wm. W. McKee
                                                      -------------------------
                                                            Wm. W. McKee
                                                            President
                                                       Chief Executive Officer

   Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the
Registrant and in the capacities and on the dates indicated.

   Signatures                         Title                      Date

Principal Executive Officer:


 /s/   Wm. W. McKee             President, Chief           March 26, 1997
----------------------------    Executive Officer and
       Wm. W. McKee             Director
 

Principal Financial and Accounting Officer:


 /s/   R. A. Byers              Chief Financial Officer    March 26, 1997
----------------------------    and Chief Accounting
       R. A. Byers              Officer


Other Directors:

 /s/   J. C. Bates              Director                   March 26, 1997
----------------------------
       J. C. Bates


 /s/   R. W. Dean               Director                   March 26, 1997
----------------------------    
       R. W. Dean                                             

                                      -15-
<PAGE>
 
                              Signatures (Cont'd)

   Signatures                         Title                      Date

 /s/    P. O. Elbert            Director                   March 26, 1997
----------------------------    
        P. O. Elbert


 /s/    W. R. Jackson           Director                   March 26, 1997
----------------------------                               
        W. R. Jackson                                          
                                                           
                                                           
 /s/    W. R. Jackson, Jr.      Director                   March 26, 1997
----------------------------                               
        W. R. Jackson, Jr.                                 
                                                           
                                                           
 /s/    W. E. Lewellen          Director                   March 26, 1997
----------------------------                               
        W. E. Lewellen                                     
                                                           
                                                           
/s/     A. J. Paddock           Director                   March 26, 1997
----------------------------                               
        A. J. Paddock                                      
                                                           
                                                           
/s/     J. W. Robinson          Director                   March 26, 1997
----------------------------                               
        J. W. Robinson                                     
                                                           
                                                           
/s/     P. J. Townsend          Director                   March 26, 1997
----------------------------    
        P. J. Townsend

                                      -16-
<PAGE>
 
                SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS
                             Pitt-Des Moines, Inc.

<TABLE>
<CAPTION>
                                                        Additions     Deductions(1)
                                                      -------------   -------------
                                        Balance at     Charged to
                                       Beginning of     Costs and       Credited       Balance at End
Description                               Period        Expenses        to Asset         of Period
-----------------------------------------------------------------------------------------------------
<S>                                    <C>            <C>             <C>              <C>

Deducted from accounts receivable
as allowance for doubtful accounts:

Year ended December 31, 1996              $868,000       $90,000         $90,000          $868,000

Year ended December 31, 1995            $  923,000      $220,000        $275,000          $868,000

Year ended December 31, 1994            $  975,000      $209,000        $261,000          $923,000
</TABLE>
---------------------
(1)  Write-off of accounts deemed to be uncollectible
<PAGE>
 
                                 EXHIBIT INDEX

3.1    Articles of Incorporation, as amended to date (filed as Exhibit 3.1 to
       the Company's quarterly report on Form 10-Q for the quarter ended
       September 30, 1989 and incorporated herein by reference)

3.2    Bylaws, as amended to date (filed as Exhibit 3.2 to the Company's
       quarterly report on Form 10-Q for the quarter ended September 30, 1989
       and incorporated herein by reference)

4.1    Amended and Restated Credit Agreement dated as of June 30, 1992 by and
       among Pitt-Des Moines, Inc. and Pittsburgh National Bank, Wells Fargo
       Bank, N.A. and American National Bank (filed as Exhibit 4.1 to the
       Company's annual report on Form 10-K for the year ended December 31, 1992
       and incorporated herein by reference)

4.2    First Amendment dated November 23, 1992 to Credit Agreement filed as
       Exhibit 4.1 hereto (filed as Exhibit 4.2 to the Company's annual report
       on Form 10-K for the year ended December 31, 1992 and incorporated herein
       by reference)

4.3    Second Amendment dated June 10, 1993 to Credit Agreement filed as Exhibit
       4.1 hereto (filed as Exhibit 4.1 to the Company's quarterly report on
       Form 10-Q for the quarter ended June 30, 1992 and incorporated herein by
       reference)

4.4    Third Amendment dated December 16, 1993 to Credit Agreement filed as
       Exhibit 4.1 hereto (filed as Exhibit 4.4 to the Company's annual report
       on Form 10-K for the year ended December 31, 1993 and incorporated herein
       by reference) 

4.5    Fourth Amendment dated June 14, 1994 to Credit Agreement filed as Exhibit
       4.1 hereto (filed as Exhibit 4.1 to the Company's quarterly report on
       Form 10-Q for the quarter ended June 30, 1994 and incorporated herein by
       reference)

4.6    Fifth Amendment dated December 8, 1994 to Credit Agreement filed as
       Exhibit 4.1 hereto (filed as Exhibit 4.6 to the Company's Annual Report
       on Form 10-K for the year ended December 31, 1994 and incorporated herein
       by reference)

4.7    Sixth Amendment dated May 31, 1995 to Credit Agreement filed as Exhibit
       4.1 hereto (filed as Exhibit 4.1 to the Company's quarterly report On
       form 10-Q for the quarter ended June 30, 1995 and incorporated herein by
       reference)

4.8    Seventh Amendment dated June 30, 1996 to Credit Agreement filed as
       Exhibit 4.1 hereto (filed as Exhibit 4.1 to the Company's quarterly
       report on Form 10-Q for the quarter ended June 30, 1996 and incorporated
       herein by reference)
<PAGE>
 
                            EXHIBIT INDEX (Cont'd)


10.1   Agreement executed by and between the Company and Wm. W. McKee (filed as
       Exhibit 10.1 to the Company's annual report on Form 10-K for the year
       ended December 31, 1990 and incorporated herein by reference)

10.2   Agreement executed by and between the Company and R. A. Byers (filed as
       Exhibit 10.1 to the Company's quarterly report on Form 10-Q for the
       quarter ended June 30, 1991 and incorporated herein by reference)

10.3   Agreement executed by and between the Company and T. R. Lloyd (filed as
       Exhibit 10.2 to the Company's quarterly report on Form 10-Q for the
       quarter ended June 30, 1991 and incorporated herein by reference)

10.4   Management Incentive Plan (filed as Exhibit 10.5 to the Company's annual
       report on Form 10-K for the year ended December 31, 1992 and incorporated
       herein by reference)

10.5   Summary of Company's 1996 Management Incentive Plan (MIP) (filed
       herewith)

10.6   Retirement Plan for PDM Outside Directors as amended, effective May 26,
       1994 (filed as Exhibit 10.7 to the Company's annual report on Form 10-K
       for the year ended December 31, 1994 and incorporated herein by
       reference)

10.7   Retirement Plan for PDM Outside Directors as amended on September 14,
       1995, effective May 26, 1994 (filed as Exhibit 10.7 to the Company's
       annual report on Form 10-K for the year ended December 31, 1995 and
       incorporated herein by reference)

10.8   Stock Option Plan of 1990 (filed as Exhibit 4.01 to the Company's
       Registration Statement No. 33-34787 on Form S-8 filed May 7, 1990 and
       incorporated herein by reference)

10.9   Investment Letter and Registration Rights Agreement dated September 21,
       1993 by and between Pitt-Des Moines, Inc. and William W. McKee, Jr.
       (filed as Exhibit 10.1 to the Company's quarterly report on Form 10-Q for
       the quarter ended September 30, 1993 and incorporated herein by
       reference)

10.10  Investment Letter and Registration Rights Agreement dated September 21,
       1993 by and between Pitt-Des Moines, Inc. and Phillip O. Elbert (filed as
       Exhibit 10.2 to the Company's quarterly report on Form 10-Q for the
       quarter ended September 30, 1993 and incorporated herein by reference)

10.11  Directors Stock Plan (filed under the Company's Registration Statement
       No. 333-13043 on Form S-8 dated September 30, 1996 and incorporated
       herein by reference)

10.12  Stock Option Agreement executed by and between the Company and P.O. 
       Elbert (filed herewith)
<PAGE>
 
                            EXHIBIT INDEX (Cont'd)


11     Computation of Per Share Earnings (filed herewith)

13     Those portions of the Annual Report to Stockholders for fiscal year ended
       December 31, 1996, which are incorporated herein by reference (filed
       herewith)

21     Subsidiaries of Pitt-Des Moines, Inc. (filed herewith)

23     Consent of Independent Auditors, Ernst & Young LLP (filed herewith)

27     Financial Data Schedule