Sunday, May 19, 2013

Silver Spring (MD) Transit Center photos

WMATA report, Silver Spring Transit Center, Montgomery Co., MD

Volume 2, pg. 290, Silver Spring Transit Center evaluation report, Montgomery Co., MD
Volume 2, pg. 291, Silver Spring Transit Center evaluation report, Montgomery Co., MD
Volume 2, pg. 293, Silver Spring Transit Center evaluation report, Montgomery Co., MD


from "conclusions", KCE report (commissioned by Montgomery County), Vol. 1, (next-to-last page):

“The in situ conditions at SSTC have been caused in varying degrees by errors and omissions of the designer, PB (Parsons Brinkerhoff), the contractor, FP (Foulger-Pratt Contracting, LLC), and its subcontractors, and the inspection and materials testing firm and Special Inspections Program Special Inspector, RBB (The Robert B. Balter Company).

Each of those contributions is noted throughout this report. Our conclusions are summarized as follows:

A. Based on our review of the information provided, the design depicted in/on the Contract Documents was not prepared in accordance with the applicable Building Code(s), the WMATA Manual of Design Criteria or Industry Standards. Based on our analysis, failure of the design to follow applicable codes and standards resulted in widespread cracking in the slabs, beams, and girders, and reductions of minimum concrete cover requirements.

B. Based on our review of the information provided, the independent inspectors, Special Inspections Program Special Inspector, Quality Assurance, Quality Control, etc. did not raise sufficient concern regarding the numerous issues that were known and/or became visible in the concrete during construction, apparently did not follow up on solutions to those issues, and did not perform their services in accordance with Industry Standard, their Contract, or the Statement of Special Inspections.

C. Based on our review of the information provided, the Contractor did not construct structural elements of the SSTC facility in accordance with the Contract Documents, ASIs, and RFI responses. The Contractor, among other things as detailed herein, placed concrete materials not in accordance with the Contract Documents.”


from "conclusions" to the WMATA report:
"Based upon the previous evaluation reports and our site observations, numerous construction defects are present in the structure. These defects include:
• Omission of the post-tensioning tendons in the Level 330 pour strips, which will necessitate replacement of the pour strips.
• Thin slabs in portions of Levels 330 and 350.
• Exposed and low concrete cover to post-tensioning tendons on the slab surfaces.
• Low entrained air content on the top section of the elevated concrete slabs.
• Extensive cracking on the elevated slab surfaces.
• Lack of details in the construction plans and construction procedures to accommodate normal thermal movements in the structure.
A strength evaluation of the as-designed and as-built structure by WDP indicated that the overall structural design of the structure was adequate. In isolated areas, the allowable stress limits were exceeded. The evaluation was based upon an analysis of representative sections and does not represent a complete review of the design. The primary design defect was the inability of the structure to accommodate normal thermal movements due to the significant restraint provided by the structural framing.
Despite the generally adequate structural design, the significant construction deficiencies have resulted in a structure that is unlikely to achieve the 50 year design service life specified in the WMATA design without implementation of a long-term protection program. The construction deficiencies include omission of post-tensioning tendons in the pour strips on Level 330, low cover to post-tensioning tendon ducts at several locations, low entrained air content in the top surface of the elevated slabs and extensive cracking on the slab surface as a result of both restrained shrinkage and finishing problems.
Based upon the extensive design and construction deficiencies, the SSTC will experience significantly higher costs for maintenance, future repairs and loss of use during repair periods compared to a properly designed and constructed facility. As-built, the SSTC is not expected to achieve its 50 year design service life without significant repairs to improve the durability of the structure."


comment (not mine) to a Washington Post article ( ):

4/30/2013 8:10 PM EDT

"Cronyism eventually produces results like this. 

1) Failure in selecting an engineering team that understood what they designing - a prestressed concrete structure that is neither a bridge nor a building, but must function as both. Selections influenced by poltical connections, contributions and firms that hire retired public agency grandees to win work (rather than technical competence and relevant expertise) Is a longstanding MD tradition. Competent structural design firms experienced with this type of construction believe they would stand no chance of being awarded this commission from Montgomery County. Must be 'connected' 

2) Failure in competing the construction work and selecting an appropriate construction contractor. Only 2 firms submitted 'proposals' for the construction, Foulger-Pratt and Clark. Why no others? Because the work was not bid, but proposals were 'evaluated' for what the County considered the best offer. Not in that loop...don't even bother submit. In the event, the County selected Foulger-Pratt a 'developer', but not generally recognized as a construction contractor. The actual construction work was subcontracted.

3) Failure in understanding the independent Inspection regime needed. The Balter Co. is a geotechnical (soil/rock) engineering and testing firm with experience in the subsurface work required for heavy civil engineering projects. But not inspecting & testing the superstructure of a prestressed concrete structure. 

4) Failure to address potential conflicts of interest. The designer, Parsons Brinckerhoff, was also assigned the project management role for the construction. This is highly unusual. Design errors identified during construction were addressed 'in house' without independent review. 

5) KCE's report is damning in it's overall findings. Embarrasingly so for the industry. Worth a read, it is written for a general audience.

Conclusion: It's for the GAO since Fed $ involved. MD and Mtgy Cty are conflicted."

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