Tool for Analysis of Early Age Transverse Cracking of Composite Bridge Decks

摘要

Computational methods and associated software were developed to compute stresses in HP concrete composite bridge decks due to temperature, shrinkage, and vehicle loading. The structural analysis program uses a layered finite element model. Before running the structural analysis code, layer-by-layer time history temperatures due to hydration heat are computed using a thermal finite element analysis program. Nodal coordinates for the thermal finite element analysis are generated from the layer thicknesses of the structural analysis finite element model. Autogeneous shrinkage, drying shrinkage, and stress relaxation due to creep are taken into account using models based on HP concrete test data. The software computes time-history residual stresses for 28 days. After 28 days an HS25 vehicle load is additionally applied. Longitudinal stress levels are printed layer by layer for comparison with the modulus of rupture and assessment of cracking. A composite bridge specimen was built in the structures testing lab in Clarkson University with thermocouple and strain gage instrumentation. After monitoring temperatures and strains for 28 days, the test specimen was loaded by a concentrated load applied by universal testing machine. Cracking under loading was observed and monitored. Software predictions were compared with test data. A one-day training course was conducted in Albany for NYSDOT engineers on August 3, 2011 to communicate the research findings and recommendations as well as provide training for the use of the developed software. This report is organized into seven parts. Each part number is associated with the corresponding task number.