Clay J. Naito, Ph.D., P.E.
Associate Professor and Associate Chair
Dept. of Civil and Environmental Engineering

Contact Information
Links

Current Research:

NSF: Development of a Blast and Ballistic Resistant Precast Concrete Armored Wall System

NEES-CR: Impact Forces from Tsunami-Driven Debris

Inspection Methods & Techniques to Determine Non Visible Corrosion of Prestressing Strands in Concrete Bridge Components

Daniel P. Jenny PCI Fellowship: Analytical Assessment of the Resistance of Precast Strucutres to Blast Effects

Development of a Seismic Design Methodology for Precast Diaphragms

Development of a Welding Procedure Specification for Field Welding of Precast Concrete Connections

Use of Polyurea for Blast Hardening of Concrete Construction

Estimation of Concrete Respone Under Varying Confinement

Evaluation of Bond Mechanics in Prestressed Concrete Applications

Horizontal Shear Capacity of Composite Beams Without Ties

Lateral Resistance of Plywood and Oriented Strand Board Sheathing After Accelerated Weathering

Past Research Projects

Performance of Bulb Tees with Self Consolidating Concrete

FRP Bridge Decks with RC Parapets

Blast Resistance of a Load Bearing Shear Wall Building

Lehigh@NEES Equipment Site

Reserarch Experinece for Undergraduates

Seismic Evaluation of a Three Story WoodFrame Apartment Building with Tuck-Under Parking

Design of RC Bridge Beam-Column Connections

Response of Waffle Slab Building Systems to Seismic Loads

Experimental Evaluation of Concrete Confined with Varying Pressure and Development of Behavioral Characteristics of Confined Concrete

Background:
In regions of high seismicity reinforced concrete plays a vital role in providing a safe structural environment. The confining action of concrete provides structural members with resistance to the elevated demands imposed by earthquakes. To improve the economy of new and rehabilitative design strategies the engineer must be able to accurately predict the response of reinforced concrete under these demands. This starts with a clear undersanding of the stress-strain behavior of confined concrete.

From the available literature, it is seen that the analytical models used for the prediction of axial stress-strain behavior of confined concrete are often based on constant confining pressure. It is experimental tests on concrete confined by Fiber Reinforced Polymer (FRP) jackets this is shown to be untrue. This is due to the characteristics of jacketing materials, which apply variable confining stresses as the concrete dilates. To address this deficiency variable confinement models have been developed. These models, however, also lack consistency in providing accurate predictions.

To develop improved modeling techniques a experimental and analytical research program is being conducted. The experimental research program examines the effect of jacketing on concrete columns under axial load. The response of glass and carbon FRP and steel jacketed concrete will be compared to the performance of concrete under tri-axial stress distributions. From these studies exisiting models will be examined and new models will be developed.

Researchers:
Clay Naito, Principal Investigator
Fatih Cetisli, Doctoral Student Researcher

Publications:
1. Naito, C., Cetisli, F., "Accuracy Improvements for Variable and Constant Confinement Concrete Models," Proceedings International Symposium on Confined Concrete, Changsha, China, June, 2004.

2.Cetisli, F. and Naito C.J., 2003, "State of the Art of Analytical Prediction for Confined Concrete," ATLSS Report, Lehigh University, No. 03-24, October, 104 pp.

Sponsors:
Pennsylvania Infrastructure Technology Alliance

Other Participants:
Republic of Turkey, Ministry of National Education

Page Last Updated Thursday, 05-Aug-2004 10:11:31 EDT