president george bush turnpike western extension
sh 161 phase 4

grand prairie, Texas

Aguirre & Fields was Deputy Structural Task Lead for the 6.5-mile stretch of SH161 from IH30 to IH20. This was NTTA’s first design-build project. We set preliminary span arrangements for 53 bridges and oversaw development of all calculation tools and validations and design protocols used by the structural design team. Other duties included organizing working point submittals to the contractor, performing inter-discipline plan reviews, and completing independent design calculations for 13 bridge packages as part of the QA/QC process.

The bridges built contained a variety of skews, alignments, and tapered widths. One direct connector included the only post-tensioned straddle bent on the project and consisted of an 87-foot-long pocketed Inverted-T bent cap utilizing eight post-tensioning tendons. Most bridges utilized Tx54 concrete girders and hammerhead single column bents or multicolumn bents. Aguirre & Fields oversaw the quality control check of a third direct connector which contained two horizontally curved, continuous steel plate girder units.

Aguirre & Fields was also Retaining Wall Task Lead for a total of 92 retaining walls including single and double tied-back drilled shaft, cantilevered drilled shaft, and mechanically-stabilized earth (MSE) retaining walls. We successfully designed all of the retaining walls to include stringent 100 psf soil loading due to anticipated swelling of native expansive soils. 

COST SAVING MEASURES:

A unique aspect of this project was the design of two cut-n-cover structures at the depressed at-grade connectors in the IH30 interchange. Due to lack of right-of-way, it was impossible to employ retaining wall systems at heights exceeding 40 feet without introduction of difficult to place struts from wall to wall. Aguirre & Fields designed two tunnel-like structures greater than 200-feet-long each consisting of 54-inch diameter drilled shaft walls covered by structural top slabs which greatly reduced the cost of the drilled shaft walls.

Photos Courtesy of AECOM