This report includes the findings of acoustic emission (AE) tests on the Fremont tied arch bridge in Portland Oregon conducted by research engineers from the Infrastructure Technology Institute of Northwestern University on March 24th, 1997.
Non-destructive evaluation (NDE) techniques have been used for a number of years to provide quality control of construction procedures for drilled shafts and driven concrete piles. In particular sonic echo and impulse response methods have been used extensively to check lengths and continuity of newly-installed foundations. In recent years, the...
A study is conducted to determine the effects on the early hydration kinetics and
compressive strength by seeding of Portland cement and alkali-activated blast furnace
slag with a pure form of calcium silicate hydrate (C-S-H). The effects of C-S-H seeding
during the early nucleation and growth period of each type...
The segmental prestressed concrete box girder of Koror-Babeldaob (KB) Bridge in Palau, which had the record span of 241 m (791 ft.), presents a striking paradigm of serviceability loss due to excessive multi-decade deflections. The data required for analysis have recently been released and are here exploited to show how...
The gradual evolution of the material properties of a cement-based material, i.e. the stiffness of cement paste, is the result of the continuous change of the microstructure with the progress of the hydration process. Based on an existing micromechanical model for the simulation of the shear and elastic modulus of...
In this paper, the correlation of reflection loss measured by an ultrasonic shear wave reflection
method and the microstructure in cement-based material is investigated. Three cement pastes
(Portland cement type I) with different water-cement ratios (0.35, 0.50 and 0.60) cured at 25
°C were examined. The ultrasonic shear wave reflection...
This presentation contains information about the project "The future of transportation... and how we'll pay for it" by Joseph L. Schofer, Department f Civil & Environmental Engineering. The presentation was delivered at the 40th Anniversary Seminar Day at Northwestern University on April 18, 2009.
This presentation provides information on the progress report of the project "Empirical Study of Life-Cycle Cost Analysis for Bridges" by Ahmad Hadavi, 2003.
Several three-dimensional effects were observed in the performance monitoring data collected during excavation for the Ford Engineering Design Center (FEDC) in Evanston, Illinois. These responses are related to lateral deformations of the soil around the excavation walls, forces in the cross-lot and diagonal bracing that supported the temporary wall and...
This paper presents the results of 159 finite element simulations conducted to define the effects of excavation geometry, i.e., length, width and depth of excavation, wall system stiffness, and factor of safety against basal heave on the 3-dimensional ground movements caused by excavation through clays. The results of the analyses...