August 30, 2014

Structural Analysis of Deeply Buried Flexible Pipe at Waste Disposal Sites

Abstract: Waste disposal sites require subsurface gravity pipe systems to collect waste leachate and safely convey it to treatment and disposal facilities. As the availability of suitable land for waste disposal sites decreases and the cost to...

July 30, 2014

Multiple Deterioration Mechanisms in Coastal Concrete Piles

By: Brett Holland, Kurtis, Kimberly E., Moser, Robert D., Kahn, Lawrence F., Aguayo, Fred, Singh, Preet M.

Abstract: The article presents a forensic investigation of precast prestressed concrete piles removed from the I-95 Turtle River Bridge, near Brunswick, GA. The piles exhibited extensive damage that led to the discovery of unexpected threats to...

July 30, 2014

How Thin is Too Thin? Evaluating slab thickness in reinforced concrete flat-plate construction

Abstract; Reinforced concrete flat-plate construction is popular among mid- and high-rise residential construction projects. It provides a great deal of flexibility in the placement of the structure’s vertical load-carrying elements (i.e....

July 29, 2014

Estimating effective damping introduced by a Pendulum Tuned Mass Damper using the Extended Kalman Filter

By: Roffel, Aaron J., Narasimhan, Sriram

Abstract: Pendulum tuned mass dampers (PTMDs) are common auxiliary damping devices used to attenuate excessive motion in tall structures. The concept of effective or equivalent damping is commonly referenced when quantifying tuned mass damper (...

July 29, 2014

Lateral Load Behavior of a Post-Tensioned Coupled Core Wall

By: Barbachyn, Steven, Kurama, Yahya C., McGinnis, Michael J., Sause, Richard, Kristen Peterson

Abstract: A 40%-scale multi-story reinforced concrete coupled core wall structure with unbonded post-tensioned coupling beams was recently tested under quasi-static reversed-cyclic lateral loading. This paper provides an overview of the design...

July 29, 2014

Numerical Framework for Seismic Collapse Assessment of Rigid Wall-Flexible Diaphragm Structures

By: Koliou, M., Filiatrault, A, Dominic Kelly, Lawson, J.

Abstract: This study focuses on the development of a two dimensional (2D) simplified numerical framework of rigid wall-flexible diaphragm (RWFD) structures that can be used to validate seismic design approaches. This type of low-rise industrial...

July 29, 2014

Development of Seismic Design Methodologies for Rigid Wall - Flexible Diaphragm Structures

By: Lawson J, Dominic Kelly, Koliou M, Filiatrault A.

Abstract: Evidence indicates that the dynamic behavior of Rigid Wall – Flexible Diaphragm (RWFD) structures is dominated by the diaphragm’s response instead of the walls’ response, and this is a significant departure from the...

July 22, 2014

New Finite Element Models and Seismic Analyses of the Telescopes at W.M. Keck Observatory

By: Frank Kan, Andrew T. Sarawit, Shawn P. Callahan, Mike L. Pollard

On 15 October 2006 a large earthquake damaged both telescopes at Keck observatory resulting in weeks of observing downtime. A significant portion of the downtime was attributed to recovery efforts repairing damage to telescope bearing journals,...

June 29, 2014

A Collaborative Approach to Temporary Earth Retention Systems for Foundations: Selecting a Sheet Pile System With Waterproofing Issues in Mind

By: Emily Appelbaum, Matthew Carlton

Abstract: Below-grade waterproofing and temporary earth retention systems should be coordinated and designed in tandem to maximize continuity of the waterproofing system. We discovered that some designers and contractors do not consistently...

June 29, 2014

Load Testing of Concrete Structures - Part 2: Test Protocols and Case Studies

By: Gustavo Tumialan, Galati, Nestore, Nanni, Antonio

Abstract: While it is usually possible to demonstrate the safety of an existing structure through calculations based on general accepted engineering principles, this is not always the case. Sometimes there are structures for which calculations...