CLOSE OVERLAY

Shrinkage and Temperature Forces in Frame Piers

Project Details
STATUS

In-Progress

PROJECT NUMBER

18-633, TR-738

START DATE

01/01/18

END DATE

02/28/23

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Behrouz Shafei

Structural Engineer, BEC

About the research

Shrinkage and temperature forces are known to have short-term and long-term effects on both the superstructures and substructures of bridges. In the substructure, such effects are more pronounced if frame piers are used, given their volumetric change is often restrained.

Considering the construction cost advantages of frame piers compared to hammerhead piers, the development of design strategies are essential to ensure the satisfactory performance of this category of piers, particularly taking into consideration the fact that they can be subjected to relatively large shrinkage and temperature forces during their service lives.

The main objective of this research was to investigate the forces developed in frame piers and their supporting foundations due to volumetric changes caused by thermal and shrinkage effects. To properly evaluate such forces, a set of existing bridges with frame piers were inspected.

A special effort was made to identify the frame piers that are susceptible to produce large forces. Such piers primarily include the ones with long pier caps and/or short columns. This is important in understanding the vulnerability of this category of piers to thermal and shrinkage effects.

Upon obtaining a qualitative assessment of the performance of existing frame piers designed with the current practices, a one-year monitoring plan was established to record the changes of strain, stress, and force at critical points of the frame piers from the time of construction and to capture both the short-term and long-term effects.

TOP