Temperature and Stress Fields of Anchorage Mass Concrete of a Suspension Bridge

Xianyu Chen

doi:10.1088/1755-1315/636/1/012025

Abstract

Because of its huge volume, the method of block and layer pouring is usually used in the construction process of suspension bridge anchorage. In order to avoid the temperature cracks of mass concrete caused by hydration heat in the construction process, a three-dimensional finite element model is established based on the anchorage of a suspension bridge. The influences of the temperature of mixture placing to mold, the thickness of layers, the ambient temperature and the maintenance measures on the temperature at the centre, the temperature difference between the top surface and middle point and the tensile stresses at the surface are analyzed. The results show that the temperature at the centre, the temperature difference between the top surface and middle point increase with the increase of the temperature of mixture placing to mold and the thickness of layers are positively correlated. When the temperature of mixture placing to mold changes from 15°C to 35°C, the temperature at the centre increases by 19.06°C, the temperature difference between the top surface and middle point increases by 10.85°C, and the tensile stresses at the surface increases by 0.72 MPa; when the thickness of layers increases from 1 m to 3 m, the temperature at the centre increases by 15.46°C, the temperature difference between the top surface and middle point increases by 16.87°C, and the tensile stresses at the surface increases by 1.51 MPa. The temperature difference between the top surface and middle point decrease with the increase of the ambient temperature, while the temperature at the centre increases with the increase of the ambient temperature. Moreover, the temperature difference between the top surface and middle point decrease with the improvement of curing conditions. Therefore, in the actual project, reducing the temperature of mixture placing to mold, the reasonable layer thickness, the suitable ambient temperature and good maintenance measures, which can effectively reduce the cracking risk of mass concrete.

Highlights

With the rapid development of the transportation industry, people's demand for long-span bridges that span wide rivers and ocean is becoming stronger and stronger
When the temperature of mixture placing to mold changes from 15°C to 35°C, the temperature at the centre increases by 19.06°C, the temperature difference between the top surface and middle point increases by 10.85°C, and the tensile stresses at the surface increases by 0.72 MPa; when the thickness of layers increases from 1 m to 3 m, the temperature at the centre increases by 15.46°C, the temperature difference between the top surface and middle point increases by 16.87°C, and the tensile stresses at the surface increases by 1.51 MPa
When the layer thickness increases from 1 m to 3 m, the temperature at the centre increases from 50.80 °C to 66.26 °C, and the temperature difference between the top surface and middle point increases from 9.74 °C to 26.61 °C, and the tensile stresses at the surface increased from 0.62 MPa to 2.13 MPa

Summary

Introduction

With the rapid development of the transportation industry, people's demand for long-span bridges that span wide rivers and ocean is becoming stronger and stronger. This paper establishes a three-dimensional finite element model, and systematically analyzes the effects of the temperature of mixture placing to mold, the thickness of layers, ambient temperature and maintenance measures on the temperature at the centre, the temperature difference between the top surface and middle point and the tensile stresses at the surface. It provides references for crack control in the construction of anchorage mass concrete in the future

Finite element method of temperature and stress fields

Influence factors of temperature and stress fields

Conclusions