The Investigation of Transverse Joints and Grouts on Full Depth Concrete Bridge Deck Panels
A set of experimental tests were performed at Virginia Tech to investigate transverse joints and blockouts on full depth concrete bridge deck panels. The joints were designed on a deck replacement project for a rural three span continuous steel girder bridge in Virginia. Two cast-in-place and four p...
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Virginia Tech
2014
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| Online Access: | http://hdl.handle.net/10919/30214 http://scholar.lib.vt.edu/theses/available/etd-12212009-101738/ |
| Summary: | A set of experimental tests were performed at Virginia Tech to investigate
transverse joints and blockouts on full depth concrete bridge deck panels. The joints
were designed on a deck replacement project for a rural three span continuous steel girder
bridge in Virginia. Two cast-in-place and four post-tensioned joints were designed and
tested in cyclical loading. Each joint was tested on a full scale two girder setup in
negative bending with a simulated HS-20 vehicle. The blockouts were built as hollow
concrete rings filled with grout and left to shrink under ambient conditions. Thirteen
combinations of different surface conditions and grouts were designed to test the bond
strength between the materials. The strain profile, cracking patterns, and ponding results
were measured for all specimens. A finite element analysis was performed and calibrated
with the laboratory results.
The cast-in-place joints and the two post-tensioned joints with 1.15 MPa (167 psi)
of initial stress experienced cracking and leaked water by the end of the tests. The two
post-tensioned joints with 2.34 MPa (340 psi) initial stress kept the deck near a tensile
stress of 1.5â (f'c) and performed the best. These transverse joints did not leak water, did
not have full depth cracking, and maintained a nearly linear strain distribution throughout
the design life. Full depth deck panel may be effectively used on continuous bridges if a
sufficient amount of post-tensioning force is applied to the transverse joints. The finite
element model provides a design tool to estimate the post-tensioning force needed to
keep the tensile stresses below the cracking limit.
The blockouts with a roughened surface or an epoxy and a grout equivalent to
Five Star Highway Patch grout had the highest bond stresses, did not leak water, and had
smaller cracks at the grout-concrete interface than the control samples. A minimum bond
strength of 2.5â (f'c) was maintained for all of the specimens with a grout equivalent to
Five Star Highway Patch. A pea gravel additive in the grout reduced shrinkage and
reduced the bond strength. The finite element model provides a design tool to estimate
cracking at the grout-surface interface. === Ph. D. |
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