New lock at Kentucky Dam: Analysis and design of precast concrete cofferdams

The historic North Torrey Pines Road Bridge in Del Mar, California, is a 15-span precast concrete tee-girder structure built in 1933. The bridge has been classified as structurally and seismically deficient and functionally obsolete, with a sufficiency rating of 19 out of 100. Through the Caltrans Retrofit and FHWA Rehabilitation Program, the structure was to be rehabilitated or replaced for improved sufficiency and to satisfy seismic life safety. The combination of complex site geology, its deteriorated state, structural irregularities, site constraints, and the requirement to preserve its historic designation presented a challenging task. The solution was a performance-based methodology, more complex than typically applied in California, which led to a unique multifaceted retrofit and rehabilitation approach. Design and analysis included detailed inelastic static analysis, secant spectral methods, and nonlinear time-history analysis with multi-support excitation. The resulting solution included ground remediation, substructure strengthening, stiffness decoupling, a replacement superstructure, and new abutments on deep foundations.

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Precast Concrete Sheetpile for the Stabilization of Road Embankment on Soft Ground Adjacent to River

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.567.451 ◽

2014 ◽

Vol 567 ◽

pp. 451-456

Author(s):

Nur Fadilah ◽

Ong Chong Yong

Keyword(s):

Precast Concrete ◽

The State ◽

Soft Ground ◽

Analysis And Design ◽

The Road ◽

Years Of Service ◽

On The Road ◽

Ground Condition

Precast concrete sheetpile designed to restore and protect a road embankment, undergoing continuous settlement in soft ground condition in Jerlun and Kuala Sanglang in the state of Kedah, Malaysia is presented. The road built on soft ground has been in service for several years with some anticipated settlements. Major defects in the form of uneven settlements were spotted after few years of service. A survey was conducted and 5 spots along a 30m to 40m long stretch experiencing about 100mm settlements relative to the centerline of the road. Several attempts have been made to backfill and re-surface the affected areas but the road conditions did not last, posing danger to motorists. Investigations have revealed slip circles did occur at the affected areas with signs of lateral movements of earths towards the river. Precast concrete sheetpiles were designed to stabilize the road embankment to prevent further lateral movements of earth due to vehicular loads on the road. Analysis and design of the sheetpile system are presented. Construction aspects related to handling, installing and finishing works at site are highlighted.

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Bond performance between SFCBs and grouted sleeves for precast concrete structures

Advances in Structural Engineering ◽

10.1177/13694332211001505 ◽

2021 ◽

pp. 136943322110015

Author(s):

Yunlou Sun ◽

Zeyang Sun ◽

Liuzhen Yao ◽

Yang Wei ◽

Gang Wu

Keyword(s):

Concrete Structure ◽

Failure Modes ◽

Precast Concrete ◽

Concrete Structures ◽

Bond Slip ◽

Analysis And Design ◽

Bond Performance ◽

Steel Bar ◽

Critical Issues ◽

Hybrid Reinforcement

A precast concrete structure reinforced by steel-fiber-reinforced polymer (FRP) composite bars (SFCBs) shows good durability and controllable post-yield stiffness, which makes this kind of structure suitable for marine infrastructure. The connection technology is one of the critical issues of a precast concrete structure with hybrid reinforcement. This paper presents an experimental study on the bond-slip testing (27 pullout specimens) of composite bars connected by a grouted deformed pipe splice (GDPS) connector with different bond lengths. The reinforcement included SFCBs and pure FRP bars. The test results showed that the failure modes could be classified into three categories: rebar pullout before or after the inner steel bar yielded, rupture of the FRP wrapped on the SFCB, and mixed failure of bar pullout with a partial fiber fracture. The average bond strength of the ordinary steel bar was approximately 146.8% that of the SFCB connector with the same anchored length. When the anchored length of the SFCB specimen was 15 d ( d: bar diameter), the specimen could be fully anchored to fracture. An explicit hardening bond-slip model considering the post-yield stiffness of the SFCB was used to predict the bond-slip behavior of the GDPS connector, and the experimental and analytical results agreed well with each other, which demonstrates that the proposed model could provided a reference for the analysis and design of connectors for SFCB-reinforced precast concrete structures.

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