<PAGE>
 
==============================================================================

                                   FORM 10-Q

                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C.  20549

                            ______________________

     [X]  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
                        SECURITIES EXCHANGE ACT OF 1934

               For the quarterly period ended September 30, 1997

                                      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)

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

      3400 Grand Avenue, Pittsburgh, PA                   15225
   (Address of Principal Executive Offices)             (Zip Code)

                                (412) 331-3000
             (Registrant's Telephone Number, including Area Code)

                             ____________________

   Indicate by check 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 
    -----    -----         

   On September 30, 1997,  3,508,456 shares of Common Stock were outstanding.

================================================================================
<PAGE>
 
                                  TABLE OF CONTENTS

                                                                 Page

Part I - Financial Information

       Item 1.   Financial statements                               3

       Item 2.   Management's discussion and analysis of
                 financial condition and results of operations     12


Part II - Other Information

       Item 1.   Legal proceedings                                  16

       Item 6.   Exhibits and reports on Form 8-K                   16


Signatures                                                          17


Exhibit Index                                                       18
 


                                      -2-
<PAGE>
 
                        Part I.  Financial Information

Item 1.  Financial Statements

                             PITT-DES MOINES, INC.
                       Consolidated Statements of Income
                                  (Unaudited)
<TABLE>
<CAPTION>

                                                     Three months ended       Nine months ended
                                                          September 30,           September 30,
                                                   --------------------   ---------------------
(in thousands, except per share amounts)             1997        1996        1997        1996
                                                   --------   ---------   ---------   ---------
 <S>                                                <C>        <C>         <C>         <C>
Earned revenue                                     $114,662   $ 120,795   $ 343,478   $ 358,410
Cost of earned revenue                              (98,969)   (104,109)   (296,209)   (311,115)
                                                   --------   ---------   ---------   ---------
    Gross profit from operations                     15,693      16,686      47,269      47,295
Selling, general and administrative expenses        (10,499)    (11,686)    (32,621)    (31,438)
                                                   --------   ---------   ---------   ---------
    Income from operations                            5,194       5,000      14,648      15,857
 
Other income/(expense):
    Interest income                                     179         365         532         808
    Interest expense                                   (196)       (315)       (428)       (906)
    Gain on sale of assets                              332         298         385         580
    Miscellaneous, net                                 (201)       (211)       (512)       (386)
                                                   --------   ---------   ---------   ---------
                                                        114         137         (23)         96
                                                   --------   ---------   ---------   ---------
     Income before income taxes                       5,308       5,137      14,625      15,953
Income taxes                                         (2,110)     (2,034)     (5,756)     (6,250)
                                                   --------   ---------   ---------   ---------
    Net income                                     $  3,198   $   3,103   $   8,869   $   9,703
                                                   ========   =========   =========   =========
Per common share:
    Net income per common share                    $   0.90   $    0.88   $    2.50   $    2.75
                                                   ========   =========   =========   =========
    Dividends paid                                 $  0.275   $    0.18   $   0.825   $    0.68
                                                   ========   =========   =========   =========
    Shares used to calculate income per share
    (in 000's)                                        3,573       3,528       3,546       3,528
                                                   ========   =========   =========   =========
 
CONSOLIDATED RETAINED EARNINGS
Balance at the beginning of year                                          $  99,344   $  89,677
    Net income                                                                8,869       9,703
    Dividends paid                                                           (2,885)     (2,382)
    Other                                                                       173          38
                                                                           --------    --------
Balance at end of period                                                   $105,501    $ 97,036
                                                                           ========    ========
</TABLE>

See Notes to Consolidated Financial Statements.


                                 -3-
<PAGE>
 
Item 1.  Financial Statements (Continued)


                             PITT-DES MOINES, INC.
                Consolidated Statements of Financial Condition

<TABLE>
<CAPTION>
                                                 September 30,       December 31,
                                                     1997                1996
                                                 -------------       ------------
(in thousands)                                   (Unaudited)
<S>                                              <C>                 <C>
Assets
 
Current Assets
 
    Cash and cash equivalents                       $ 15,379           $ 16,815
    Accounts receivable including retentions                     
    (less allowances:  1997-$1,075; 1996-$868)        83,892             72,424
    Inventories                                       18,211             18,192
    Costs and estimated profits in excess                        
     of billings                                      36,710             36,831
    Deferred income taxes                              4,475              4,475
    Prepaid expenses                                   1,651                822
                                                    --------           --------
                                                                 
       Total Current Assets                          160,318            149,559
                                                                 
Other Assets                                           6,838              8,097
                                                                 
Goodwill                                               5,698                203
                                                                 
Property, Plant and Equipment                                    
    Land                                               7,274              7,274
    Buildings                                         35,983             35,213
    Machinery and equipment                           68,658             65,457
                                                    --------           --------
                                                     111,915            107,944
Allowances for depreciation                          (69,362)           (65,918)
                                                    --------           --------
    Net Property, Plant and Equipment                 42,553             42,026
                                                    --------           --------
                                                    $215,407           $199,885
                                                    ========           ========
</TABLE>

See Notes to Consolidated Financial Statements.


                                      -4-
<PAGE>
 
Item 1.  Financial Statements (Continued)



                             PITT-DES MOINES, INC.
                Consolidated Statements of Financial Condition
<TABLE>
<CAPTION>
                                                            September 30,       December 31,
                                                                1997                1996
                                                            -------------       ------------
(in thousands)                                              (Unaudited)
<S>                                                         <C>                 <C>
 
Liabilities
 
Current Liabilities
    Accounts payable                                          $ 32,791           $ 41,593
    Accrued compensation, related taxes and benefits            11,619             12,005
    Other accrued expenses                                       3,356              2,064
    Billings in excess of costs and estimated profits            8,257             10,731
    Income taxes                                                   (37)               494
    Casualty and liability insurance                             9,439              7,133
                                                              --------           --------
       Total Current Liabilities                                65,425             74,020
                                                                         
Revolving Credit Facility                                       17,000                  0
                                                                         
Deferred Income Taxes                                            5,744              5,699
                                                                         
Minority Interest                                                2,095              1,546
                                                                         
Contingencies and Commitments                                            
                                                                         
Stockholders' Equity                                                     
                                                                         
    Preferred stock - par value $.01 per share;                          
     authorized 3,000,000 shares; issued - none                          
    Common stock - no par value; authorized                              
     15,000,000 shares; issued 4,473,234 shares                 33,549             33,549
    Retained earnings                                          105,501             99,344
                                                              --------           --------
                                                               139,050            132,893
    Treasury stock at cost                                               
     (1997-964,777 shares; 1996-990,233 shares)                (13,907)           (14,273)
                                                              --------           --------
       Total Stockholders' Equity                              125,143            118,620
                                                              --------           --------
                                                              $215,407           $199,885
                                                              ========           ========
</TABLE>

See Notes to Consolidated Financial Statements.


                                      -5-
<PAGE>
 
Item 1.  Financial Statements (Continued)


                             PITT-DES MOINES, INC.
                     Consolidated Statements of Cash Flows
                                  (Unaudited)
<TABLE>
<CAPTION>
                                                        For the nine months ended
                                                                September 30,
                                                        -------------------------
(in thousands)                                            1997             1996
                                                        --------         --------
<S>                                                     <C>              <C>

Cash Flow From Operating Activities
 Net income                                              $  8,869       $  9,703
 Adjustments to reconcile net income to net                  
  cash utilized by operating activities:                     
   Depreciation                                             4,381          4,463
   Gain on sale of assets                                    (385)          (580)
   Minority interest, net of dividends paid                    99            152
   Other non-cash credits, net                               (240)          (180)
 Change in operating assets and liabilities                  
    (using) providing cash:                                  
   Accounts receivable                                     (8,239)       (14,190)
   Inventories                                              2,895         (1,226)
   Prepaid expenses                                          (816)          (335)
   Costs, estimated profits and billings, net              (2,288)         7,099
   Accounts payable                                       (11,134)        (7,737)
   Accrued liabilities                                      2,933            732
   Income taxes                                              (711)          (202)
                                                         --------       --------
 Net cash utilized by operating activities                 (4,636)        (2,301)
                                                             
Cash Flows from Investing Activities                         
 Capital expenditures                                      (4,773)        (2,853)
 Proceeds from sale of assets                                 587            722
 Acquisitions, net of cash acquired                        (8,342)             0
 Change in investments and other assets                     1,075            (75)
                                                         --------       --------
 Net cash utilized by investing activities                (11,453)        (2,206)
                                                             
Cash Flows from Financing Activities                         
 Proceeds from revolving credit facility                   17,000          8,000
 Payments of revolving credit facility                          0         (6,000)
 Dividends paid                                            (2,885)        (2,382)
 Other                                                        538            124
                                                         --------       --------
 Net cash provided by financing activities                 14,653           (258)
                                                         --------       --------
 Decrease in cash and cash equivalents                     (1,436)        (4,765)
 Cash and cash equivalents at beginning of year            16,815          9,508
                                                         --------       --------
Cash and cash equivalents at end of period               $ 15,379       $  4,743
                                                         ========       ========
</TABLE>

See Notes to Consolidated Financial Statements.

                                      -6-
<PAGE>
 
Item 1.  Financial Statements (Continued)


                             PITT-DES MOINES, INC.
                  Notes to Consolidated Financial Statements
                                  (Unaudited)

Note A.  Basis of Presentation

The accompanying unaudited consolidated financial statements have been prepared
in accordance with generally accepted accounting principles for interim
financial information and with the instructions to Form 10-Q and Article 10 of
Regulation S-X.  Accordingly, they do not include all of the information and
footnotes required by generally accepted accounting principles for complete
financial statements.  In the opinion of management, all adjustments (consisting
of normal recurring accruals) considered necessary for a fair presentation have
been included.  Operating results for the nine months ended September 30, 1997
are not necessarily indicative of the results that may be expected for the year
ending December 31, 1997.  The December 31, 1996 Consolidated Statement of
Financial Condition was derived from audited financial statements.  For further
information, refer to the consolidated financial statements and footnotes
thereto included in the Company's Annual Report on Form 10-K for the year ended
December 31, 1996.

Note B.  Acquisitions

General Steel Corporation - On January 31, 1997, the Company acquired 90% of the
stock of General Steel Corporation, a steel service center, located in
Vancouver, Washington.

Candraft Detailing, Inc. - On March 10, 1997, the Company acquired the stock of
Candraft Detailing, Inc., an engineering and drafting company, located in
Vancouver, British Columbia.

Sheffield Steel Products - On October 7, 1997, the Company acquired the assets
of Sheffield Steel Products, a bridge fabricator, located in Palatka, Florida.

These acquisitions were accounted for as purchases and, accordingly, the assets
acquired and liabilities assumed were recorded at their estimated fair value at
the date of acquisition.  The total costs of these acquisitions were $12.5
million.  Due to the immaterial impact of these acquisitions to the results of
operations, pro forma information has not been provided.



                                      -7-
<PAGE>
 
Item 1.    Financial Statements (Continued)

Note C.  Costs and Estimated Profits on Uncompleted Contracts

Costs and estimated profits on uncompleted contracts are summarized as follows:

<TABLE>
<CAPTION>
 
                                                     September 30,   December 31,
(in thousands)                                            1997           1996
                                                     --------------  -------------
<S>                                                  <C>             <C>
Costs incurred on uncompleted contracts                $ 625,575      $ 646,534
Estimated profits                                         77,427         88,729
                                                       ---------      ---------
                                                         703,002        735,263
Less:  Billings to date                                 (674,549)      (709,163)
                                                       ---------      ---------
                                                       $  28,453      $  26,100
                                                       =========      =========
</TABLE>

Costs, estimated profits and billings on uncompleted contracts are included in
the accompanying Consolidated Statements of Financial Condition under the
following captions:

<TABLE>
<CAPTION>
 
                                                     September 30,   December 31,
(in thousands)                                            1997           1996
                                                     --------------  -------------
<S>                                                  <C>             <C>
Costs and estimated profits in excess of billings      $36,710        $ 36,831
Billings in excess of costs and estimated profits       (8,257)        (10,731)
                                                       -------        --------
                                                       $28,453        $ 26,100
                                                       =======        ========
</TABLE>

Included in costs and estimated profits in excess of billings on uncompleted
contracts was approximately $6.5 million at September 30, 1997 and December 31,
1996, respectively, relating to an unapproved change order arising from a
dispute over design and specification changes.

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 an unapproved change order arising from a dispute over
design and specification changes.  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.



                                      -8-
<PAGE>
 
Item 1.  Financial Statements (Continued)

Note D.  Contingencies

As previously reported, on November 3, 1993, an accident occurred at the
construction site of a new United States Post Office in Chicago where the
Company's Steel Construction business segment was in the process of erecting the
steel structure of the building. Two men were killed and five seriously injured
when a portion of the erected steel collapsed. Various personal injury claims
had been asserted against the Company, and others, as a result of the accident
(the "Personal Injury Cases"). As of December 31, 1996, the Company's insurance
carriers have settled all of the claims against the Company in the Personal
Injury Cases in which the Company was a defendant without the Company incurring
any additional cost.

An investigation of the November 3, 1993 accident was conducted by the Federal
Occupational Safety and Health Administration (OSHA) and the Justice Department
as required by OSHA law.  OSHA has cited the Company for safety violations and
has assessed $147,000 in civil penalties.  The Company contested the assessment
(the "Civil Penalty Proceeding") and in an order dated April 28, 1995, an
administrative law judge dismissed OSHA's case assessing civil penalties.  OSHA
appealed that dismissal and in an order dated March 24, 1997, the Occupational
Safety and Health Review Commission reversed the dismissal and entered an order
staying any further proceedings in the Civil Penalty Proceeding pending
disposition of the OSHA Criminal Proceeding (See below.)

As a result of the OSHA/Justice Department investigation, on August 23, 1996,
the Company was served with an indictment issued by a grand jury for the United
States District Court for the Northern District of Illinois (the "OSHA Criminal
Proceeding").  The indictment alleged that the Company is guilty of two
misdemeanors for violations of the Occupational Safety Health Act (and
regulations promulgated thereunder) concerning the erection of structural steel
members around the time of the November 3, 1993 accident and that such
violations caused the deaths of the two men killed in the accident.

In the OSHA Criminal Proceeding, a jury trial commenced on July 15, 1997 and on
July 31, 1997 the jury returned a verdict of guilty against the Company for two
counts of misdemeanor violations of OSHA regulations resulting in the deaths of
two men killed in the accident.  The Department of Justice has reported that the
maximum criminal fines and penalties which can be assessed, as a result of the
conviction is $1.0 million.

In an order dated October 28, 1997 the District Court denied the Company's post-
trial motions in the OSHA Criminal Proceeding.  A sentencing hearing has not yet
been scheduled in this matter.  The Company will file an appeal with the United
States Court of Appeals for the Seventh Circuit immediately following
sentencing.

Management and counsel believe that the Company has significant and meritorious
points for sustaining the Company's appeal in the OSHA Criminal Proceeding.



                                      -9-
<PAGE>
 
Item 1.  Financial Statements (Continued)

Note D.  Contingencies (Continued)

Any criminal fines or penalties to be assessed against the Company in this
matter will be the subject of the sentencing hearing, yet to be scheduled.
Management believes that any fines, penalties and costs of defense in this
matter, which are uninsured, will not be material to the Company's financial
condition, although they could be material to the Company's reported results of
operations for the period in which such amounts are incurred. As a result of the
Justice Department's actions, other claims, actions, or proceedings may be
instituted against the Company. While the Company has no reason to believe that
any such claim, action or proceeding will be instituted against it, the Company
cannot predict the likelihood of such a claim, action or proceeding being
instituted against it, and cannot assess the availability of any insurance
coverage or the possibility or materiality of an adverse result in the event of
any such claim, action or proceeding in advance of a claim, action or proceeding
being instituted.

On June 20, 1996 the Company was served with a subpoena to appear and produce
documents before the Grand Jury of the United States District Court for the
Western District of Wisconsin in connection with the United States Department of
Justice Antitrust Division's investigation of bid rigging and other criminal
violations in the steel bridge fabrication industry.  The Company has been
informed that it is not presently the target of the investigation but that it
and other companies in the steel bridge fabrication industry are the subjects of
the investigation.

The Company has no reason to believe that it will become a target of the
investigation or that a criminal action will be instituted against it in these
matters.  If the Company became a target or a criminal investigation were
instituted, the Company believes that it has significant and meritorious
defenses to any such charges and intends to vigorously defend them.

There are various claims and legal proceedings against the Company arising from
the normal course of business.  Although counsel is unable to predict with
certainty the ultimate outcome, management and counsel believe the Company has
significant and meritorious defenses to any claims, and intend to pursue them
vigorously.

The Company's operations, including idle facilities and other property, are
subject to and affected by federal, state and local laws and regulations
regarding the protection of the environment.  The Company accrues for
environmental costs where such obligations are either known or considered
probable and can be reasonably estimated.

The Company is participating as a potentially responsible party (PRP) at three
different sites pursuant to proceedings under the Comprehensive Environmental
Response, Compensation and Liability Act (CERCLA).  Other parties have also been
identified as PRP's at the sites.  Investigative and/or remedial activities are
ongoing.  The Company believes, based upon information presently available to
it, that such future costs will not have a material effect on the Company's
financial position, results of operations or liquidity.  Additionally, amounts



                                      -10-
<PAGE>
 
Item 1.  Financial Statements (Continued)

Note D.  Contingencies (Continued)

reflected in results of operations and in the statements of financial condition
during the three years ended December 31, 1996 and during the nine months ended
September 30, 1997, have also not been material. However, the imposition of more
stringent requirements under environmental laws or regulations, new developments
or changes regarding site cleanup costs or the allocation of such costs among
PRP's or a determination that the Company is potentially responsible for the
release of hazardous substances at sites other than those currently identified,
could result in additional costs.

Management believes that the ultimate outcome of any matters currently pending
against the Company will not materially affect the financial position of the
Company although they could be material to the reported results of operations
for the period in which they occur.

This quarterly report on Form 10-Q contains certain forward-looking statements
as to the outcome of various claims and legal proceedings.  Actual results may
differ with respect to such claims and proceedings as a result of factors over
which the Company does not have any control, including, but not limited to, new
developments, changes in the laws or regulations and the positions taken by the
opposing parties, the courts or the finders of fact.



                                      -11-
<PAGE>
 
Item 2.  Management's Discussion and Analysis of Financial Condition and Results
of Operations

RESULTS OF OPERATIONS

THREE MONTHS ENDED SEPTEMBER 30, 1997 COMPARED WITH THREE MONTHS ENDED
SEPTEMBER 30, 1996.

The Company reported net income of $3.2 million, or 90 cents per share, on
earned revenue of $114.7 million for the quarter ended September 30, 1997. These
results compare with net income of $3.1 million, or 88 cents per share, on
earned revenue of $120.8 million for the same quarter last year. Earned revenue
for the current quarter decreased $6.1 million when compared with the previous
year quarter. The most significant impact on earned revenue was attributable to
the closure of the Melrose Park, Illinois fabrication facility.

The Engineered Construction Division reported a 9.6 percent decrease in earned
revenue from $49.6 million to $44.8 million for the third quarter of 1997.
Income from operations decreased from $2.3 million to $2.1 million for the
quarter ended September 30, 1997.  Selling, general and administrative (SG&A)
expense, as a percentage of earned revenue, remained relatively unchanged at
approximately 8.6 percent for the quarters ended September 30, 1996 and 1997.
New awards for the quarter of $54.5 million increased $15 million from $39.5
million for the quarter ended September 30, 1996.  This resulted in a
significant increase in backlog to $157 million at September 30, 1997 versus $97
million at September 30, 1996.

For the current quarter, Steel Construction reported earned revenue of $19
million and income from operations of $1.4 million.  These results compare with
earned revenue of $26.7 million and income from operations of $1.3 million for
the quarter ended September 30, 1996.  SG&A expense as a percentage of earned
revenue, increased to the current level of 10.4 percent from 5.8 percent from
the previous year quarter.  The most significant impact on current results was
the closure of the Melrose Park structural steel fabricating facility.  This
facility contributed approximately 25 percent to Steel Construction earned
revenue during the third quarter of 1996.  For the current quarter, this
facility reported a decrease in earned revenue and reported an operating loss
due to reduced volume and exit costs related to the closure when compared with
the same quarter in 1996.  New awards for the quarter of $36.4 million
represents a significant increase when compared with new awards $27.3 million
for the same quarter in 1996.  This resulted in a backlog level of $66.3 million
at September 30, 1997 versus $76.8 million at September 30, 1996.  As indicated
in "Costs and Estimated Profits on Uncompleted Contracts" in Notes to
Consolidated Financial Statements, included in costs and estimated profits in
excess of billings on uncompleted contracts at September 30, 1997 was
approximately $6.5 million relating to an unapproved change order arising from a
dispute over design and specification changes.



                                      -12-
<PAGE>
 
Item 2.  Management's Discussion and Analysis of Financial Condition and Results
of Operations (Continued)

RESULTS OF OPERATIONS (Continued)

THREE MONTHS ENDED SEPTEMBER 30, 1997 COMPARED WITH THREE MONTHS ENDED
SEPTEMBER 30, 1996. (Continued)

Steel Service Centers earned revenue for the current quarter of $51 million
represents a 14 percent improvement from 1996 and also represents 44 percent of
PDM's consolidated earned revenue for the third quarter of 1997. Additionally,
income from operations of $4.2 million increased 7 percent when compared with
the third quarter of 1996. A significant portion of these increases,
particularly in earned revenue, can be attributed to the first quarter
acquisition of General Steel Corporation. Current SG&A expense, as a percentage
of earned revenue, increased to 6.9 percent from 6.6 percent from the same
period in 1996.



NINE MONTHS ENDED SEPTEMBER 30, 1997 COMPARED WITH NINE MONTHS ENDED
SEPTEMBER 30, 1996.

For the nine months ended September 30, 1997, net income totaled $8.9 million,
or $2.50 per share, on earned revenue of $343.5 million.  These results compare
with net income of $9.7 million, or $2.75 per share, on earned revenue of $358.4
million for the same period of last year.  As previously reported, a one-time
event, the closure of our Melrose Park structural steel fabricating facility,
had a negative impact on 1997 results.

For the nine months ended September 30, 1997, Engineered Construction reported
earned revenue of $133.8 million and income from operations of $4.1 million.
These results compare with earned revenue of $143.8 million and income from
operations of $5.8 million for the same period in 1996.  New awards of $188.8
million increased $40.8 million from $148 million for the nine months ended
September 30, 1996.  SG&A expense, as a percentage of earned revenue, for the
previous year's nine months period was 8.3 percent and increased to 9.2 percent
for the current nine month period.  This increase was primarily the result of an
increase in sales and estimating costs due to pre-bid engineering activity.

Steel Construction reported earned revenue of $68.8 million and income from
operations of $4.4 million for the nine months ended September 30, 1997.  These
results compare with earned revenue of $93.7 million and income from operations
of $7.5 million for the same period in 1996.  The most significant impact on
results for the Steel Construction business segment was the previously reported
closure of the Melrose Park structural steel fabricating facility.  This
facility contributed $30.5 million in earned revenue for the nine months ended
September 30, 1996 versus $4.6 million in earned revenue for 1997.



                                      -13-
<PAGE>
 
Item 2.  Management's Discussion and Analysis of Financial Condition and Results
of Operations (Continued)

RESULTS OF OPERATIONS (Continued)

NINE MONTHS ENDED SEPTEMBER 30, 1997 COMPARED WITH NINE MONTHS ENDED 
SEPTEMBER 30, 1996. (Continued)

Steel Service Centers earned revenue was $141.4 million for the nine months
ended September 30, 1997 compared with $122.3 million for the same period in
1996.  Income from operations of $12.2 million currently increased $2.3 million
when compared with the same period in 1996.  SG&A expense, as a percentage of
earned revenue, was 7.2 percent for the current period, when compared with 7
percent for the previous year's period. A significant portion of the increases
in earned revenue and SG&A expenses was attributed to the acquisition of General
Steel Corporation during the first quarter of 1997.

In February 1997, the Financial Accounting Standards Board issued Statement No.
128, "Earnings Per Share" which is required to be adopted by the Company for the
year ended December 31, 1997.  The impact of Statement 128 on the calculation of
earnings per share for the Company is not expected to be material.

In June 1997, the Financial Accounting Standards Board issued Statement No. 131,
"Disclosures about Segments of an Enterprise and Related Information" which is
effective for financial statements for fiscal years beginning after December 15,
1997.  The adoption of Statement No. 131 will have no impact on the Company's
consolidated results of operations, financial position or cash flows, but will 
result in certain changes in required disclosures of segment information.

As indicated in the "Contingencies" section of the Notes to Consolidated
Financial Statements, the Company's future results of operations could be
materially adversely affected by the Company's conviction on July 31, 1997 of
two misdemeanors for violations of the Occupational Safety Health Act (and
regulations promulgated thereunder)(see Note D "Contingencies" Notes to
Consolidated Financial Statements).



                                      -14-
<PAGE>
 
Item 2.  Management's Discussion and Analysis of Financial Condition and Results
of Operations (Continued)

LIQUIDITY AND CAPITAL RESOURCES

During the nine months ended September 30, 1997, the Company's primary sources
of liquidity were cash and cash equivalents and proceeds from the revolving
credit facility which were used for investing activities and to fund the growth
in working capital.  Working capital increased $19.4 million from $75.5 million
on December 31, 1996 to $94.9 million currently.  On September 30, 1997, cash
and cash equivalents were $15.4 million compared with $16.8 million on December
31, 1996.

Net cash utilized by operating activities of $4.6 million increased by $2.3
million when compared with the same period in 1996. Changes in operating assets
and liabilities, primarily accounts receivable and costs, estimated profits and
billings (net), accounted for the net cash outflows. These components are
affected by the mix, stage of completion and commercial terms of contracts.

The acquisition of General Steel Corporation on January 31, 1997, accounted for
a substantial portion of the cash utilized by investing activities.  The Company
intends to continue to evaluate and selectively pursue opportunities for growth
or expansion of its business.  Capital expenditures, exclusive of acquisitions,
of $4.8 million for the period ended September 30, 1997 were primarily for plant
machinery and equipment and the previously announced construction of a new
structural steel fabricating facility in Eloy, Arizona.  This facility is slated
to be operational by the first quarter of 1998.  Capital expenditures of $2.9
million were primarily for plant machinery and equipment during the period ended
September 30, 1996.  Total capital expenditures, exclusive of business
acquisitions, for the year ending December 31, 1997 should approximate $5.7
million.

Cash provided by financing activities was primarily from proceeds from the
revolving credit facility.  The Company paid cash dividends of $2.9 million
($.825 per share) during the period ended September 30, 1997.  Cash dividends of
$2.4 million ($.68 per share) were paid during the same period in 1996.  The
payment of future dividends will be evaluated based on business conditions.

The Company has on hand and access to sufficient sources of funds to meet its
anticipated operating, expansion and capital needs.  These sources include cash
on hand and the unused portion of a $40.0 million unsecured revolving credit
facility which matures December 31, 1999.  This facility contains an annual
option to renew for an additional one-year period, subject to lender approval.
On November 10, 1997, $17 million of borrowings and $8.5 million of stand-by
letters of credit were outstanding under this credit facility.

Item 3.  Quantitative and Qualitative Disclosures About Market Risk

Not applicable.


                                     -15-
<PAGE>
 
                          Part II - Other Information


Item 1.  Legal Proceedings

         Refer to Part I Item 1, Notes C and D of the Notes to Consolidated
         Financial Statements for information, which information is incorporated
         herein by reference.

Item 6.  Exhibits and Reports on Form 8-K

   (a)   Exhibits

         Exhibit 11.1 -  Computation of earnings per share for the three months
                         ended September 30, 1997 and 1996.

         Exhibit 11.2 -  Computation of earnings per share for the nine months
                         ended September 30, 1997 and 1996.

         Exhibit 27 - Financial Data Schedule.

   (b)   Reports on Form 8-K.

         Item 5. Other Events

         A Form 8-K dated July 31, 1997, was filed to report the Company's plan
         to appeal a jury's verdict in the trial related to the November 1993
         accident at the United States Postal Service building in Chicago,
         Illinois.



                                     -16-
<PAGE>
 
                                  Signatures
                                       


Pursuant to the requirements 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.
                                     -------------------------------
                                         (Registrant)




                                     Principal Executive Officer:



Date:  November 13, 1997             By: /s/  Wm. W. McKee
                                         ---------------------------- 
                                              Wm. W. McKee
                                              (President and
                                              Chief Executive Officer)



                                     Principal Financial Officer:



Date:  November 13, 1997             By: /s/  R. A. Byers
                                         ----------------------------
                                              R. A. Byers
                                            (Vice President
                                         Finance and Treasurer)


                                     -17-
<PAGE>
 
                                 EXHIBIT INDEX


Exhibit
Number
-------    

11.1   Computation of earnings per share for the three months ended
          September 30, 1997 and 1996.

11.2   Computation of earnings per share for the nine months ended
          September 30, 1997 and 1996.

27     Financial Data Schedule.




                                     -18-