An ongoing study investigating the response of a reinforced concrete building rehabifitated after the 1985 Me&% City earthquake is presented. As part of this program, the behavior under cyclic loads of reinforced concrete columns rehabilitated with steel jackets made of angles and straps is king experimentally assessed. First results on the response of the budding and on the behavior of rehabilitated columns are shown. So far, Building BL has responded elastically, with no damage under recent events. It is apparent that BL response follows the soil fundamental frequency. A first look at the behavior of steel jackets made of angles and straps Wugh two column units, indicates that strength and energy dissipation capacities can be improved, especially in undamaged columns.

This paper deals with the measurement of physical properties (mechanical, thermal, acoustical) of various formulations of concrete containing vegetable particles. Such material is mde up with hemp shives mixed with lime binders. Shives are very porous and so liglitweight. Thus, this concrete presents a high porosity related to the microscopic porosity of the shives and the macroscopic porosity due to the arrangement of particles. Moreover, this material presents a ductile behavior and can bears high strain without been destroyed. Depending on the binder proportion, the mechanical properties of vegetable concrete cover a wide range: maximum stress in between 0.4 and 1.2 MPa, Young madulus in between 20 and 90 MPa, strain at maximum stress in between 4 and 10%. The thermal conductivity ranges from 0.06 to 0.11 W.m-1.K-1, sound absorption between 0.5 and 1. The final aim of this study is to optimize the formulation of vegetable concrete according to its use (wall, floor, roof. . .). A theoretical model made with self-consistent method allows to calculate precisely the coefficient of conductivity l as a function of the mixture proportion and the compactness level. A comparison with experimental measurements shows a good accuracy of the results.

The Horsetail Creek Bridge (HCB), constructed in 1912, is located along the Historic Columbia River Highway in Oregon. The cross beams of this historic structure were found to be 50 percent deficient in flexure and 94 percent deficient in shear, mainly due to the traffic loads increase. Analysis of the alternative designs indicated that glass FRP (GFRP) laminates would be most suitable for shear strengthening, while carbon FRP (CFRP) laminates would be best for flexural capacity enhancement. Concurrently, four full size beams, as similar as possible to the actual bridge beams, were constructed to simulate the retrofit of the bridge. One of the beams served as a control; one beam was strengthened for shear capacity increase only; one beam was reinforced with CFRP for flexure; and one beam was reinforced with CFRP for flexure and GFRP for shear. Results revealed that addition of either GFRP or CFRP composites strengthening provided static capacity increase of 45 percent compared to the control beam. The beam strengthened with CFRP for flexure and GFRP for shear, which simulated the HCB cross beams after the retrofit, exhibited nearly 100 percent of moment capacity increase. Post cracking stiffness of all beams was increased, primarily due to the flexural CFRP laminates. Results suggested that capacity of the experimental beam, retrofitted in the same fashion as the bridge, should exceed the bridge design load of 720 kN-m (after strengthening), sustaining up to 868 kN-m of applied moment. The addition of GFRP for shear alone was sufficient to offset the lack of steel stirrups in the actual bridge, allowing for a conventionally reinforced concrete beam with significant shear deficiency to fail by yielding of the tension steel. The ultimate deflections of the shear GFRP reinforced beam were nearly twice those of the control shear-deficient beam. The experimental beam retrofitted with only CFRP for flexure failed as a result of diagonal tension cracking at a load 45% greater than the control beam. A design method for flexure and shear was proposed before the onset of this experimental study and used on the HCB. The design procedure for flexure was refined and allowed for predicting the response of the beam at any applied moment. The flexural design procedure includes provisions for non-crushing failure modes, and was shown to be slightly conservative using the design material properties.

An optical fiber monitoring system was designed and built into a three-span high performance concrete highway bridge. The Rio Puerco Bridge, locgted 15 miles west of Albuquerque, is the first bridge to be built using HPC in New Mexico. The bridge has 3 spans with length of 29 to 30 m. It is designed to be simply supported for dead load and continuous for live load. HPC was used for the cast-in-place concrete deck and the prestressed concrete beams. A total of 40 long-gage (2-m long) deformation sensors, along with thermocouples were installed in parallel pairs at the top and bottom flange of the girders. The embedded seams measured temperature and deformations at the supports, at quarter spans and at mid-span. Measurements were collected during: Beam Fabrication (Casting of the beams, Steam curing, Strand release, Storage), Bridge Constructio~ and Service. The data collected was analyzed to calculate the prestress losses in the girders, compare the losses to the predicted losses using available code methods, and get a better understanding of the properties and behavior of high performance concrete. The project is funded by the Federal Highway Administration, the New Mexico State Highway and Transportation Department, and the National Science Foundation.

This paper presents a rational approach used for the evaluation of inplace concrete pavement with flexural strength requirements. During the construction of a concrete paving project at McCarran International Airport in Las Vegas, Nevada, data was developed from the testing of over 450 specimens of concrete beams, cylinders, and cores representing samples from nearly 170 locations. Hexural, compressive, and splitting tensile strength testing was performed on these samples obtained from locations where comparison between the different types of strength tests was possible. Relationships between this data were evaluated and a rational approach to the evaluation of in-place concrete for compliance with flexural strength requirements was developed. This approach that begins with trial batch data and includes cast and cored specimen, could be applied to other concrete paving projects with similar concerns.