FALL 2018

ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.

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Page 23 of 51

Built from 1952 to 1953, the second Interstate 10 bridge crossing the Neches River in Beaumont, Tex., was a marvel of slide-rule engineering and built-up, riveted steel plate girder construction. Unfortunately, it had a subtle flaw. When the bridge was widened in 1976, the longitudinal slab construction joint was placed directly over the original outside girder. The original 6¼-in.-thick slab was placed in 20-ft segments with transverse construction joints between segments; however, no longitudinal reinforcement connected the segments. Although the 1976 plans showed that the existing transverse reinforcement would be cleaned and straightened into the new construction, results over time showed that this detail may not have been followed. By 2000, the Texas Department of Transportation's (TxDOT's) maintenance forces were out on the deck almost monthly to patch the slab punchouts occurring at those corners between the longitudinal construction joint and the original deck segments. The time had come to evaluate other options. Redecking the bridge was considered; h o w e v e r, a s t h e o l d d e c k w a s removed, suspected disintegration of the top flange of the original exterior girder under the leaking longitudinal construction joint was confirmed. TxDOT did not want to assess and then possibly repair 3450 ft of girder on this extremely busy and important corridor, so it decided to replace the old bridge with concrete girder approaches and segmental main spans. Project Specifications Whereas the old bridge was a single structure, the new crossing consists of eastbound and westbound twin structures, with just a 1-in.-wide gap at the roadway tie-ins and a 12-ft-wide separation at the segmental portion. The twin-structure design was selected for the Purple Heart Memorial Bridge for traffic control and inspection reasons. Each new structure is 70 ft wide and carries four lanes of traffic. There are 23 approach spans of prestressed concrete girders flanking the three-span balanced- cantilever segmental main unit over the Neches River. Despite being more than 35 miles inland from the Gulf of Mexico, the Neches River is navigable under the bridge. Therefore, U.S. Coast Guard clearances had to be provided. The previous bridge had a main span of 240 ft and, because the alignment of the new Purple Heart Memorial Bridge was over the old bridge, the new main span had to extend beyond t h e e x i s t i n g p i e r s . A b a l a n c e d - cantilever segmental bridge proved to be the best choice for the main unit, ultimately providing 193 ft of horizontal navigation clearance. profile PURPLE HEART MEMORIAL BRIDGE / BEAUMONT, TEXAS BRIDGE DESIGN ENGINEER: Texas Department of Transportation, Austin, Tex. PRIME CONTRACTOR: Williams Brothers Construction Company, Houston, Tex. PRECASTER: Valley Prestress Products, Eagle Lake, Tex.—a PCI-certified producer POST-TENSIONING CONTRACTOR: Williams Brothers Construction Company, Houston, Tex. OTHER MATERIAL SUPPLIERS: Formwork, form travelers, and erection equipment: Williams Brothers Construction Company, Houston, Tex.; reinforcement fabricator: CMC Steel, Seguin, Tex.; bearings: Seismic Energy Products, Athens, Tex.; expansion joints: CMC Capital City Steel, Buda, Tex.; post-tensioning ducts and anchors: DYWIDAG-Systems International, Mansfield, Tex.; and post-tensioning steel: Insteel Wire Products, Gallatin, Tenn. Because the main piers are relatively short, twin parallel-wall bents were used to soften the longitudinal stiffness of the supports for the Purple Heart Memorial Bridge. All Photos and Figures: Texas Department of Transportation Beaumont District. Purple Heart Memorial Bridge over the Neches River by Kenneth Wiemers, Texas Department of Transportation, Amy Smith, HDR, and Tom Stout, Stantec 22 | ASPIRE Fall 2018 P R O J E C T

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