01592695

Component

Twenty two test parapets were constructed as part of this project to evaluate different approaches to address premature cracking. The experiments included the use of deeper saw cuts through glass fiber reinforced polymer (GFRP) reinforcement or field cut steel reinforcement, with the saw cut depth increased from 1 ½ inches (38 mm) to 3 ½ inches (89 mm). Another experimental modification was the use of polypropylene fibers in the mixture at two different dosage rates, 1 lb./yd³ (0.59 kg/m³) and 2 lb./yd³ (1.19 kg/m³). The research team monitored bridge parapets during and immediately after construction. The stiffness gain of parapets and joint cracking were monitored using ultrasonic pulse velocity (UPV). Seven of the nine control parapets displayed cracking, and only five of the thirteen experimental parapets had mid-panel cracking. Both parapets with Vandal Protection Fence (VPF) posts showed cracks near the posts. Deeper saw cuts allowed more joints to crack at early stages, and prevented uncontrolled cracking. The parapets with fibers showed no measurable improvement over the parapets without fibers in regards to preventing shrinkage and temperature cracking. Reducing the joint spacing over negative tension areas was found to reduce uncontrolled bridge parapet cracking. However, since the experimental parapets with the reduced joint spacing were coupled with another modification of either the polypropylene fibers or the deeper saw cut, it was hard to determine if this alone would solve uncontrolled bridge parapet cracking.

This paper was sponsored by TRB committee AFF80 Standing Committee on Structural Fiber Reinforced Polymers.

01584066

16-2141

English

15p

2016

Transportation Research Board 95th Annual Meeting

Digital/other

References; Tables

Bridge design; Concrete bridges; Cracking; Fiber reinforced polymers; Glass fiber reinforced concrete; Joint construction; Parapets; Polypropylene; Shrinkage

Ohio

Bridges and other structures; Construction; Design; Highways

Transportation Research Board Annual Meeting 2016 Paper #16-2141

TRIS, TRB, ATRI

Jan 12 2016 4:56PM