<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 June 30, 1998

                                      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.)

10200 Grogan's Mill Road, Suite 300, The Woodlands, TX          77380
      (Address of Principal Executive Offices)               (Zip Code)

                                (281) 774-2200
             (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 June 30, 1998,  7,226,290 shares of Common Stock were outstanding.


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<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 4.   Submission of matters to a vote of security holders   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        Six months ended
                                                           June 30,                 June 30,
                                                   ----------------------    ----------------------
(in thousands, except per share amounts               1998         1997         1998         1997
                                                   ---------    ---------    ---------    ---------
<S>                                                <C>         <C>          <C>          <C> 
Earned revenue                                     $ 140,188    $ 119,235    $ 263,558    $ 228,816
Cost of earned revenue                              (118,983)    (101,763)    (223,278)    (197,240)
                                                   ---------    ---------    ---------    ---------
     Gross profit from operations                     21,205       17,472       40,280       31,576
Selling, general and administrative expenses         (14,039)     (11,430)     (25,591)     (22,122)
                                                   ---------    ---------    ---------    ---------
     Income from operations                            7,166        6,042       14,689        9,454
 
Other income/(expense):
     Interest income                                     203          159          342          353
     Interest expense                                   (479)        (160)        (743)        (232)
     Gain on sale of assets                                9           16           27           53
     Miscellaneous, net                                  (95)        (185)        (692)        (311)
                                                   ---------    ---------    ---------    ---------
                                                        (362)        (170)      (1,066)        (137)
                                                   ---------    ---------    ---------    ---------
     Income before income taxes                        6,804        5,872       13,623        9,317
Income taxes                                          (2,654)      (2,302)      (5,305)      (3,646)
                                                   ---------    ---------    ---------    ---------
     Net income                                    $   4,150    $   3,570    $   8,318    $   5,671
                                                   =========    =========    =========    =========
Per common share:
     Earnings per share                            $    0.59    $    0.51    $    1.18    $    0.81
     Earnings per share assuming dilution          $    0.55    $    0.50    $    1.13    $    0.80
Shares used to calculate:  (in thousands)
     Earnings per share                                7,067        6,997        7,050        6,981
     Earnings per share - assuming dilution            7,531        7,091        7,364        7,068
 
Cash dividend                                      $    0.15     $  0.138    $    0.30    $   0.275
 
CONSOLIDATED RETAINED EARNINGS
Balance at the beginning of year                                             $ 110,096    $  99,344
     Net income                                                                  8,318        5,671
     Dividends paid                                                             (2,186)      (1,920)
     Other                                                                         207          125
                                                                             ---------    ---------
                                                                             $ 116,435    $ 103,220
                                                                             =========    ==========
</TABLE>

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

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


                                                    June 30, December 31,
                                                      1998       1997
                                                    --------   --------
(in thousands)                                     (Unaudited)

Assets

Current Assets
 
     Cash and cash equivalents                       $ 14,852   $ 12,037
     Accounts receivable including retentions
     (less allowances:  1998-$547; 1997-$1,059)        96,320     78,216
     Inventories                                       23,713     26,236
     Costs and estimated profits in excess
      of billings                                      45,364     46,493
     Deferred income taxes                              4,527      4,527
     Prepaid expenses                                   1,468      1,086
                                                    --------   --------
       Total Current Assets                          186,244    168,595
 
Other Assets                                           8,767       7,793
                                                                        
Goodwill                                               6,116       6,172
                                                                        
Property, Plant and Equipment                                           
     Land                                              7,612       7,611
     Buildings                                        43,815      41,630
     Machinery and equipment                          74,520      69,972
                                                    --------    --------
                                                     125,947     119,213
Allowances for depreciation                          (72,969)    (70,349)
                                                    --------    --------
     Net Property, Plant and Equipment                52,978      48,864
                                                    --------    --------
Total Assets                                        $254,105    $231,424
                                                    ========    ======== 

See Notes to Consolidated Financial Statements.

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

                             PITT-DES MOINES, INC.
                Consolidated Statements of Financial Condition
<TABLE>
<CAPTION>
                                                            June 30,     December 31,
                                                              1998           1997
                                                            --------     ------------
(in thousands)                                             (Unaudited)
<S>                                                        <C>           <C>
Liabilities
 
Current Liabilities
    Accounts payable                                         $ 29,622        $ 48,811
    Accrued compensation, related taxes and benefits           13,785          12,492
    Other accrued expenses                                      4,807           2,283
    Billings in excess of costs and estimated profits          25,602           9,906
    Income taxes                                                1,223           2,889
    Casualty and liability insurance                            7,121           6,041
                                                             --------        --------
       Total Current Liabilities                               82,160          82,422

Revolving Credit Facility                                      26,500          11,000
 
Deferred Income Taxes                                           5,802           5,802
 
Minority Interest                                               3,223           2,537
 
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 8,946,468 shares                33,549          33,549
    Retained earnings                                         116,435         110,096
                                                             --------        --------
                                                              149,984         143,645
    Treasury stock at cost
     (1998-1,720,178 shares; 1997-1,933,094 shares)           (13,564)        (13,982)
                                                             --------        --------
       Total Stockholders' Equity                             136,420         129,663
                                                             --------        --------
Total Liabilities and Stockholders' Equity                   $254,105        $231,424
                                                             ========        ========
</TABLE>
See Notes to Consolidated Financial Statements.

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


                             PITT-DES MOINES, INC.
                     Consolidated Statements of Cash Flows
                                  (Unaudited)

                                                        Six months ended
                                                            June 30,
                                                       --------------------
(in thousands)                                           1998         1997
                                                       --------     -------
Cash Flow From Operating Activities
 Net income                                            $  8,318     $ 5,671
 Adjustments to reconcile net income to net
  cash utilized by operating activities:
   Depreciation                                           3,112       3,082
   Gain on sale of assets                                   (27)        (53)
   Minority interest, net of dividends paid                 686         (46)
   Other non-cash (credits) debits, net                   1,250        (120)
 Change in operating assets and liabilities
  (using) providing cash:
   Accounts receivable                                  (18,104)     (3,478)
   Inventories                                            2,523       2,777
   Prepaid expenses                                        (382)     (1,095)
   Costs, estimated profits and billings, net            16,825      (6,997)
   Accounts payable                                     (19,189)     (5,295)
   Accrued liabilities                                    3,147       1,162
   Income taxes                                          (1,666)        (52)
                                                       --------     -------
 Net cash utilized by operating activities               (3,507)     (4,444)
 
Cash Flows from Investing Activities
 Capital expenditures                                    (7,281)     (2,359)
 Proceeds from sale of assets                                82         137
 Acquisitions, net of cash acquired                           -      (8,342)
 Change in investments and other assets                    (418)      1,018
                                                       --------     -------
 Net cash utilized by investing activities               (7,617)     (9,546)
 
Cash Flows from Financing Activities
 Proceeds from revolving credit facility                 15,500       9,000
 Dividends paid                                          (2,186)     (1,920)
 Other                                                      625         340
                                                       --------     -------
 Net cash provided by financing activities               13,939       7,420
                                                       --------     -------
 (Decrease) increase in cash and cash equivalents         2,815      (6,570)
 Cash and cash equivalents at beginning of year          12,037      16,815
                                                       --------     -------
Cash and cash equivalents at end of period             $ 14,852     $10,245
                                                       ========     =======

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 six months ended June 30, 1998 are not
necessarily indicative of the results that may be expected for the year ending
December 31, 1998.  The December 31, 1997 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, 1997.

Comprehensive Income

Statement of Financial Accounting Standards No. 130, "Reporting Comprehensive
Income" (SFAS No. 130), is effective January 1, 1998.  This Statement
establishes standards for reporting and display of comprehensive income and its
components.  Comprehensive income includes net income and all other changes in
stockholders' equity except those resulting from investments and distributions
to owners.  The Company has had no significant reportable transactions under the
provisions of SFAS No. 130 for the periods reported.

Software Costs

Statement of Position 98-1, "Accounting for the Costs of Computer Software
Developed or Obtained for Internal Use" (SOP 98-1) requires the capitalization
of certain costs incurred in connection with developing or obtaining software
for internal use.  Qualifying software costs are capitalized and amortized over
the estimated useful life of the software.  Prior to the adoption of SOP 98-1,
software costs were expensed as incurred.  Restatement of prior-year financial
statements was not permitted.  The adoption of SOP 98-1 did not have a material
impact on the Corporation's financial position or results of operations.

Segment Disclosure

Statement of Financial Accounting Standards No. 131, "Disclosures about Segments
of an Enterprise and Related Information" (SFAS No. 131), establishes new
standards for reporting information about operating segments in interim and
annual financial statements.  This statement is effective for 1998.  Management
does not anticipate that the adoption of this statement will have a significant
effect on the Company's reported segments.

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

Note A.   Basis of Presentation (Continued)

Derivative Instruments and Hedging Activities

Statement of Financial Accounting Standards No. 133, "Accounting for Derivative
Instruments and Hedging Activities" (SFAS No. 133) is effective in years
starting after June 15, 1999.  SFAS No. 133 addresses the accounting for
derivative instruments, including certain derivative instruments embedded in
other contracts, and hedging activities.  The Company does not currently utilize
derivatives or engage in hedging activities; therefore, management does not
anticipate that the adoption of this statement will have a material impact on
the Company's financial position or results of operations.
 
Note B.   Earnings Per Share

The following table sets forth the computation of earnings per share and
earnings per share assuming dilution:

                                             Three months        Six months
                                            ended June 30,     ended June 30,
                                            ---------------   ----------------
                                             1998     1997      1998     1997
                                            ------   ------   --------  ------

(in thousands, except per share amounts)
Numerator:
Net income                                  $4,150   $3,570   $  8,318  $5,671
                                            ======   ======   ========  ======

Denominator:
Weighted-average shares                      7,067    6,997      7,050   6,981
Employee stock options                         464       94        314      87
                                            ------   ------   --------  ------
Weighted-average shares-assuming dilution    7,531    7,091      7,364   7,068
                                            ======   ======   ========  ======
 
Earnings per share                          $ 0.59   $ 0.51   $   1.18  $ 0.81
                                            ======   ======   ========  ======
 
Earnings per share-assuming dilution        $ 0.55   $ 0.50   $   1.13  $ 0.80
                                            ======   ======   ========  ======
 
Note C.  Costs and Estimated Profits on Uncompleted Contracts
 
Costs and estimated profits on uncompleted contracts are summarized as follows:
 
                                                 June 30,    December 31,
(in thousands)                                    1998           1997
                                                ---------      ---------
Costs incurred on uncompleted contracts         $ 672,833      $ 679,157
Estimated profits                                  91,771         91,177
                                                ---------      ---------
                                                  764,604        770,334
Less:  Billings to date                          (744,842)      (733,747)
                                                ---------      ---------
                                                $  19,762      $  36,587
                                                =========      =========

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

Note C.   Costs and Estimated Profits on Uncompleted Contracts (Continued)

Costs, estimated profits and billings on uncompleted contracts are included in
the accompanying Consolidated Statements of Financial Condition under the
following captions:
 
                                                       June 30,   December 31,
(in thousands)                                           1998         1997
                                                       --------   ------------
Costs and estimated profits in excess of billings      $ 45,364     $46,493
Billings in excess of costs and estimated profits       (25,602)     (9,906)
                                                       --------     -------
                                                       $ 19,762     $36,587
                                                       ========     =======

Included in costs and estimated profits in excess of billings on uncompleted
contracts was approximately $6.5 million at June 30, 1998 and December 31, 1997,
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 to a project under construction.  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.

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 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").
By December 31, 1996, the Company's insurance carriers 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.

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

Note D.   Contingencies (Continued)

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. 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 pending final disposition of the OSHA Criminal
Proceeding.

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"). On July 31, 1997, in the OSHA Criminal Proceeding, a 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. A
sentencing hearing was held on March 20, 1998 in the OSHA Criminal Proceeding
and the Company was fined $1,000,250 and the fine was paid on March 27, 1998.
The Company filed an appeal on March 20, 1998, with the United States Court of
Appeals for the Seventh Circuit seeking various forms of relief (Pitt-Des
Moines, Inc. v. United States of America No. 98-1767).

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

As a result of the Justice Department's actions, other claims, actions, or
proceedings may be instituted against the Company.  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 a 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 the target of the investigation at present but that it
and other companies in the steel bridge fabrication industry are the subjects of
the investigation.

While the investigation remains pending, the Company does not believe it will
become a target of the investigation or that a criminal action will be
instituted against it in these matters. If the Company becomes a target or a
criminal investigation were instituted, the Company believes that it would have
significant and meritorious defenses to any such charges and would vigorously
defend against them.

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

Note D.   Contingencies (Continued)

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
reflected in results of operations and in the statements of financial condition
during the three years ended December 31, 1997 and during the six months ended
June 30, 1998, 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 matter 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.

Note E.  Common Stock Split

On May 7, 1998, the Company declared a two for one stock split effective in the
form of a stock dividend payable June 26, 1998 to stockholders of record at the
close of business on June 12, 1998.  Per share amounts, market prices, number of
shares and stock option amounts have been adjusted for the stock split for all
periods presented.

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

RESULTS OF OPERATIONS

THREE MONTHS ENDED JUNE 30, 1998 COMPARED WITH THREE MONTHS ENDED JUNE 30, 1997.

The Company reported net income of $4.2 million, or $0.55 per share, on earned
revenue of $140.2 million for the quarter ended June 30, 1998.  During the
quarter ended June 30, 1998, $1.8 million of compensation expense was recognized
under an incentive stock plan.  Excluding the impact of the charge, net income
would have been $5.2 million, or $0.69 per share.  These results compare with
net income of $3.6 million, or $.50 per share, on earned revenue of $119.2
million for the quarter ended June 30, 1997.

ENGINEERING AND CONSTRUCTION

The Engineering and Construction segment reported a 25 percent increase in
earned revenue from $69.8 million to $86.9 million for the second quarter of
1998.  Income from operations increased $1.3 million from $4.4 million a year
ago to $5.7 million for the current quarter.  Performance of contracts related
to Liquid and Cryogenic Storage, Water Storage, and Steel Bridges accounted for
the majority of the increases in both earned revenue and income from operations.
Selling, general and administrative (S,G&A) expense as a percentage of earned
revenue improved nearly one percentage point, decreasing to 7.4 percent from 8.3
percent for the period ended June 30, 1997.  New awards rose $22.8 million, or
33 percent, to $91.6 million for the quarter ended June 30, 1998 compared with
$68.8 million for the comparable period of 1997. The growth in new awards
resulted in a strong backlog level of $268.1 million at June 30, 1998 versus
$196.5 million at June 30, 1997.  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 June 30, 1998, was approximately $6.5 million relating to an
unapproved change order arising from a dispute over design and specification
changes.

STEEL DISTRIBUTION

Steel Distribution reported earned revenue of $54.2 million, an 11 percent
increase from $48.9 million in earned revenue for the three months ended June
30, 1997.  Income from operations decreased 4 percent to $4.5 million for the
current quarter from $4.7 million for the same period in 1997.  S,G&A expense as
a percentage of earned revenue dropped to 6.5 percent from 7.1 percent for the
period ended June 30, 1997.


                                        

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

RESULTS OF OPERATIONS (Continued)

SIX MONTHS ENDED JUNE 30, 1998 COMPARED WITH SIX MONTHS ENDED JUNE 30, 1997.

The Company reported net income of $8.3 million, or $1.13 per share, on earned
revenue of $263.6 million for the six months ended June 30, 1998.  During the
six months ended June 30, 1998, $1.8 million of compensation expense was
recognized under an incentive stock plan.  Excluding the impact of the charge,
net income would have been $9.4 million, or $1.27 per share.  These results
compare with net income of $5.7 million, or $.80 per share, on earned revenue of
$228.8 million for the six months ended June 30, 1997.

ENGINEERING AND CONSTRUCTION

The Engineering and Construction segment reported a 22 percent increase in
earned revenue from $134.2 million to $163.8 million for the first half of 1998.
Income from operations increased $5.2 million from $7.0 million a year ago to
$12.3 million for the first six months of 1998.  Performance of contracts
related to Liquid and Cryogenic Storage, Water Storage, and Steel Bridges
accounted for the majority of the increases in both earned revenue and income
from operations.  Selling, general and administrative (S,G&A) expense as a
percentage of earned revenue dropped to 7.5 percent from 8.1 percent for the
period ended June 30, 1998.  New awards of $180.8 million, for the first half of
1998, increased $18.6 million from $162.2 million for the first six months of
1997.

STEEL DISTRIBUTION

Steel Distribution reported earned revenue of $101.5 million, a 12 percent
increase from $90.4 million in earned revenue for the six months ended June 30,
1997.  Increased steel service center volumes coupled with incremental revenues
from General Steel Corporation, an acquisition completed during the first
quarter of 1997, contributed to the improvement in earned revenue. Income from
operations increased 1 percent to $8.0 million for the first six months of 1998.
S,G&A expense as a percentage of earned revenue improved to 6.9 percent from 7.5
percent for the comparable period of the prior year.

OTHER

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).

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

OTHER (Continued)

The Company initiated a review of its software systems in 1997 in view of the
fact that certain systems will not properly recognize dates after the year 1999,
which could cause those systems to produce invalid results. This is commonly
referred to as "the Year 2000 problem". The company has substantially completed
the assessment phase of all major systems and, in some cases, has made the
required changes. Based upon the results of the work done to date, which is
expensed as incurred, the Company believes that the remaining work will be
completed in a timely manner and that the overall cost of such work will not be
material. There can be no assurance that the estimated cost of addressing this 
issue will not be negatively impacted by further analysis of the Company's
systems, as well as reliance on its customers and outside vendors systems. If
the Company and third parties upon which it relies are unable to address this
issue in a timely manner, it could result in a material financial risk to the
Company. In order to assure that this does not occur, the Company plans to
devote all resources required to resolve any significant year 2000 issues in a
timely manner.

LIQUIDITY AND CAPITAL RESOURCES

During the six months ended June 30, 1998, the Company's primary sources of
liquidity were proceeds from the revolving credit facility and cash flow
generated from operations which were used for investing activities and to fund
the growth in working capital.  Working capital increased $17.9 million from
$86.2 million at December 31, 1997 to $104.1 million currently.  On June 30,
1998, cash and cash equivalents were $14.9 million compared with $12.0 million
on December 31, 1997.

Net cash utilized by operating activities of $3.5 million decreased by $0.9
million when compared with the same period in 1997.  The favorable change in
certain operating assets and liabilities, primarily costs, estimated profits and
billings (net), partially offset by changes in accounts receivable and accounts
payable, accounted for the decrease in net cash outflows.  The changes in
operating assets and liabilities from period to period are affected by the mix,
stage of completion and commercial terms of contracts.

Net cash utilized by investing activities of $7.6 million for the six months
ended June 30, 1998 was primarily for capital expenditures.  These expenditures
consisted primarily of plant machinery and equipment and construction of the new
structural steel fabricating facility in Eloy, Arizona, which began operating in
April 1998.

Cash utilized by investing activities of $9.5 million during the first half of
1997 related primarily to the acquisition of General Steel Corporation.  The
Company intends to continue to evaluate and selectively pursue opportunities for
growth or expansion of its business through investment in or acquisition of
complementary businesses.  The Company expects that any such acquisitions will
be financed from cash on hand or available funds under the Company's revolving
credit facility.

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

LIQUIDITY AND CAPITAL RESOURCES (Continued)

Cash provided by financing activities consisted primarily of proceeds from the
revolving credit facility.  The Company paid cash dividends of $2.2 million, or
$0.30 per share, and $1.9 million, or $0.275 per share, during the six months
ended June 30, 1998, and 1997, respectively.

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 August 11, 1998, $26.5 million of borrowings and $7.8 million of stand-by
letters of credit were outstanding under this credit facility.

FORWARD-LOOKING STATEMENTS

Any of the comments in this quarterly report that refer to the Company's
estimated or future results, margins on existing or future projects, long-term
profitability and demand and growth trends for Pitt-Des Moines, Inc., are
forward-looking and reflect the Company's current analysis of existing trends
and information.  Actual results may differ materially from current expectations
or projections based on a number of factors affecting the Company's businesses.
The Company's estimates of future performance depend on, among other things, the
likelihood of receiving certain new awards.  While these estimates are based on
the good faith judgment of management, these estimates frequently change based
on new facts which become available.  In addition, the timing of receipt of
revenue by the Company from engineering and construction projects can be
affected by a number of factors outside the control of the Company.  The
Company's businesses are also subject to fluctuations in demand and to changing
global economic and political conditions which are beyond the control of the
Company and may cause actual results to differ from the forward-looking
statements contained in this quarterly report.

These forward-looking statements represent the Company's judgment only as of the
date of this quarterly report.  As a result, the reader is cautioned not to rely
on these forward-looking statements.  The Company disclaims any intent or
obligation to update these forward-looking statements.

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 4.   Submission of Matters to a Vote of Security Holders

          On May 7, 1998, the Company held its annual stockholders meeting. Only
          holders of common stock of record at the close of business on March
          16, 1998 were entitled to notice of and to vote at the Annual Meeting.
          As of that date, the Company had outstanding 3,524,687 shares of
          common stock. The three matters voted upon at the Annual Meeting were
          the election of three directors, the ratification of the appointment
          of Ernst & Young LLP as auditors for the year ending December 31,
          1998, and approval of the Pitt-Des Moines, Inc. Long Term Incentive
          Stock Plan of 1997.

          Each of the Company's nominees for director was reelected at the
          Annual Meeting. The total number of votes cast for the election of
          directors was 3,080,682. Following is a separate tabulation with
          respect to each director:
 
                                    Votes For      Votes Withheld
                                    ---------      --------------

            W. R. Jackson, Jr.      2,829,546          251,136
            A. J. Paddock           2,746,392          334,290
            P. J. Townsend          2,829,805          250,877

         The total number of votes cast for the ratification of the appointment
         of Ernst & Young LLP as auditors for the year ending December 31, 1998,
         was 3,080,682 with 3,036,611 votes for, 42,753 votes against and 1,318
         votes abstained.

         The total number of votes cast for the ratification of approval of the
         Pitt-Des Moines, Inc. Long Term Incentive Stock Plan of 1997 was
         2,790,831 with 1,969,783 votes for, 764,767 votes against and 56,281
         votes abstained.

         There were no broker non-votes with respect to the three matters voted
         upon.

Item 6.  Exhibits and Reports on Form 8-K

     (a) Exhibits

         (10) - Material Contracts.
       
                10.1  Long Term Incentive Stock Plan of 1997, effective 
                      November 6, 1997 (filed herewith)

         (27) - Financial Data Schedule.

     (b) Reports on Form 8-K.

         There have been no reports on Form 8-K filed by the Company
         during the quarter ended June 30, 1998.

                                      -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:  August 13, 1998               By: /s/ Wm. W. McKee
                                         -----------------------------
                                             Wm. W. McKee
                                            (President and
                                         Chief Executive Officer)



                                     Principal Financial Officer:



Date:  August 13, 1998               By: /s/ R. A. Byers
                                         -----------------------------
                                             R. A. Byers
                                           (Vice President
                                         Finance and Treasurer)


 

                                      -17-
<PAGE>
 
                                 EXHIBIT INDEX


Exhibit
Number
-------    

 10.1      Long Term Incentive Stock Plan of 1997, effective November 6, 1997
             (filed herewith)

 27        Financial Data Schedule.

                                      -18-