Chadd Lane Jian Zhao Assistant Professor WisCamp Undergraduate Research Summer 2009 University of Wisconsin Milwaukee

Motivation:  Structural safety  Cracks in the cement, broken anchors, or shifting of the beams.  Maximize structural safety  Saving time and money

 Behavior of anchor connections  Concrete cracking in tension  Current design regulations  Limited guidance

 How does one maximize structural safety with the number of anchors, anchor design, and location?  How does one disperse the weight of a large beam evenly among all the anchors?

Concrete Spall Cone— Steel Breakage— Anchor Pullout— Bond Failure— Edge Distance and Spacing Reduction—

 Spalled concrete — split, chip, or to break into smaller pieces

 A material can be loaded in: a) compression b) tension c) shear

 Computer simulation  failure rate of cement and anchors  Real life seismic loading simulation.  Confirm computer simulations  How the cement and anchors should look when they fail.  Understand the full nature of cement and anchors.  Calculations  How to disperse the weight of the large beam evenly amongst all anchors evenly

 One of the anchor bolts was fractured  The other bent under a combined tension and shear action.  The top layer of concrete spalled such that the hairpin, with an intention to help the anchor connection to resist shear, was displaced outside the anchor connection.  Note that the failure of the anchor connection might have contributed to the total collapse of the industrial building.

 The experimental tests include the ongoing single-anchor tests at UWM and the anchor group tests (to be conducted at Illinois in 2010).  Anchors in every test group are subjected to these loadings: tension and shear  The loading frame shown right are set for the various loading patterns. Meanwhile  4YLUqOysI 4YLUqOysI

 The anchor position is chosen to enable concrete breakout failure.  The same configurations will be cast and tested with various anchor reinforcements to explore practical and effective reinforcement details that can prevent the concrete breakout failure modes.  Headed bars and reinforcement cages are under consideration.

 The single anchor tests will be simulated using finite element models to optimize the anchor reinforcement details.  The proposed design procedures will be incorporated in the MathCAD programs.

 Using the NEES facility at the University of Illinois.  Obtain detailed experimental - cyclic shear and combined tension-shear.  Evaluate current seismic anchor design provisions and develop new  design methodologies and the use of anchor reinforcements.  Create fiber-based connection interface models.  Promote a timely transfer of knowledge

 This UWM project is being led by Dr. Zhao  Two graduate students Joshua Johnston and Derek Petersen from UWM and one graduate student from UC are working on the project.  Two undergraduate students Alice Muehlbauer and Chadd Lane.

 Seismic behavior and design of cast-in- place anchors/studs using NSF NEES facility and local resources.  Anchor tests that simulate a combination of concrete breakout failure under shear and/or tension.  The focus will be also on the improvement of anchor behavior through using anchor reinforcements.  The research program will generate critical knowledge that advances the seismic design of anchor connections, as well as providing essential information for future revision of anchorage design regulations.

 Dr. Zhao and his team  WisCamp and McNair Staff and students  All other people that played a roll in this great experience.