Design and Construction Challenges of an Integral Abutment Bridge in a Soft Soil Condition

Integral bridge Lightweight fill Expansion joint elimination Dynamic load test
["Vosogh, Amirhossein","Hassan, Munzer"] 2024-01-01 期刊论文
The integral abutment bridge concept allows removal of expansion joints, bearings, piles for horizontal earth loads, and other uneconomical details. These details not only add to construction costs but also increase the maintenance work and expenses. When expansion joints are eliminated from a bridge, thermal stresses must be accounted for in the design. This paper describes the design challenges for a 45.6 m one-span integral abutment bridge, nearby Gatineau, Quebec, Canada. According to the geotechnical report, the soil under the foundation of the bridge consists of a 1.0-5.4 m granular embankment mixed with organic material and layers of wood chips, 15 m layered deposits of granular and cohesive soils, and a 35.7 to 40.8 m thick clay that is laid on a till layer. Because a 5.3 m granular backfill of abutments would lead to remarkable consolidation settlement and maintenance issues, it was decided to substitute 3.7 m of the granular backfill with a lightweight material to minimize the long-term settlement problem. A 3D bridge model in CSiBridge was used to simulate the construction stages and nonlinear behavior of soil around the piles to predict the induced efforts in the bridge due to different loads, including thermal and deck shrinkage loads. Structural design of piles was accomplished by taking into account the plastic hinge at the top of the piles and estimating the buckling free length of piles based on analysis of pile under lateral load in L-PILE software. While some Canadian provinces have developed standard details for approach slab joints, Quebec's ministry of transportation (MTQ) does not propose any standard expansion joint detail for integral bridges. Therefore, the typical strip seal expansion joints detail of MTQ was adapted for this project to reduce water infiltration inside the joint even though it is away from the deck and is located at the end of approach slab. During the construction, the result of test piles revealed that excess pore water pressure due to pile driving operation needs some time to disappear. Thus, minimum waiting times for the main stages of construction were defined. [GRAPHICS] .
来源平台:PROCEEDINGS OF THE CANADIAN SOCIETY FOR CIVIL ENGINEERING ANNUAL CONFERENCE 2023, VOL 11, CSCE 2023