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

Contact Information

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

Applicability of Self Consolidating Concrete for Use in Precast Bridge Beam Construction

Use of self consolidating concrete (SCC) has become popular with nonstructural applications. In an effort to assess the structural applicability in precast prestressed bridge construction a research program was conducted. SCC and conventional high early strength concrete (HESC) were compared through an extensive series of plastic and hardened material tests, and through the examination of full-scale SCC and HESC bulb tee beams. Two mix designs were developed using similar aggregates and cements with variations in admixtures and batch weights. The SCC design and conventional mix design produced comparable strength gain, modulus of rupture, splitting tension, shrinkage, creep, hardened and plastic air, freeze thaw resistance, and chloride permeability. Results indicate that the SCC mix design meets the requirements for DOT use in PA, NJ, NY, VA, and MA. Four bulb tee beams were fabricated and non-destructively evaluated. Measurements taken during release of prestress indicated that the beams have a transfer length lower than PCI recommendations. Cost benefit analysis of fabrication time, material cost, and aesthetics indicated a cost savings for SCC over conventional high early strength material.

Clay Naito, Principal Investigator
Greg Parent, Graduate Student Researcher
Geoffrey Brunn, Research Assistant

Pennsylvania Infrastructure Technology Alliance
Schuylkill Products, Inc.
Degussa Admixtures, Inc.
Pennsylvania DOT
Prestressed Concrete Association of Pennsylvania

Other Participants:
Federal Highway Administration
Delaware DOT
Maryland State Highway Administration
New Enterprise Stone & Lime Co.
New Jersey DOT
New York State DOT

1. Naito, C., Brunn, G., Parent, G., and Tate, T., "PITA Project PIT-457-04 Comparative Performance of High Early Strength and Self Consolidating Concrete for Use in Precast Bridge Beam Construction - Final Report," ATLSS Report No.05-03, ATLSS Center, Lehigh University, June 2005, 102 pages.
Download (5.7Mb)

2. Naito, C., and Hoover, M., "Applicability of Self Consolidating Concrete for Use in Precast Bridge Beam Construction," Fourth International RILEM Symposium on Self-Compacting Concrete, October 30-November 2, 2005, Chicago, Illinois.

Page Last Updated Wednesday, 29-Jun-2005 12:06:47 EDT