Details:

Creators:
Kalabon, Amy ; Hedges, Lauren ; Delatte, Norbert
Kalabon, Amy ; Hedges, Lauren ; Delatte, Norbert Less -
Corporate Creators:
Cleveland State University. Dept. of Civil and Environmental Engineering
Corporate Contributors:
United States. Federal Highway Administration
Subject/TRT Terms:
[+]
Bridge Construction Bridge Design Cracking Cutting Fiber Reinforced Concrete Field Tests Joints (Engineering) Parapets
Publication/ Report Number:
FHWA/OH-2015/5
Resource Type:
Tech Report
Geographical Coverage:
United States
Corporate Publisher:
Ohio. Dept. of Transportation. Office of Statewide Planning and Research
Abstract:
A total of 22 test parapets was 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. This included instrumentation with embedded maturity

sensors to capture temperature history of the parapets, using Command Center technology. Researchers also

observed and documented parapet construction. It was important to note any constructability issues that may

arise that may be related to the proposed solutions, since they would potentially impact the cost of

implementation. Crack surveys were performed once formwork was removed and sawcutting had been

completed. The stiffness gain of parapets and joint cracking were monitored using ultrasonic pulse velocity (UPV)

technology. While all of the eight control bridges showed mid-panel cracking, only four of the twelve experimental

bridges had mid-panel cracking. Both parapets with Vandal Protection Fence (VPF) posts showed cracks near the

posts. The main purpose of using GFRP or field cut steel reinforcement with the 3.5 inch (89 mm) deep saw cut is

to create a weakened plane at the control joint through the gap provided in the reinforcement, in order initiate

cracking at the joints and reduce the risk of cracking elsewhere on the parapet. From the data gathered, this

modification 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.


Format:
PDF
Funding:
SJN 134818
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:03b811098f1a218eb1bcb43901a388622783ea1f3bb563fbd616aa6c5a886591
Download URL:
https://rosap.ntl.bts.gov/view/dot/28692/dot_28692_DS1.pdf
File Type:

Supporting Files

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