By CA User 0 Comments

Construction Consulting for the San Roque Dam and Reservoir

Located in the Island of Luzon on the Agno River, approximately 200 km from Manila in the Philippines, this dam and reservoir project intended to produce non-polluting, hydroelectric power, provide water irrigation, reduce downstream flooding, and improve water quality in the San Roque River. The project included a 200-meter-high rock fill dam to be the twelfth highest embankment dam in the world. CA provided construction troubleshooting services and recommendations for concrete mixture proportions, concrete production, and concrete placement and finishing for the casting of mass concrete sections utilizing high performance concrete for the concrete spillway and tunnel sections. Among the challenges being faced was the production of concrete to be placed on very steep slopes and long tunnel sections while achieving a smooth finish with reduced cracking to resist the forces of high water flows. CA was also involved in developing repair recommendations for the rehabilitation of some of the concrete already in place.

By CA User 0 Comments

NDT Services at a Distribution Center Concrete Pavement Parking Lot

CA conducted an investigation to determine the cause(s) of the distress in the exterior concrete pavement at a distribution center facility in Houston, Texas. The investigation consisted of a comprehensive assessment of the structural integrity of the pavement using destructive and non-destructive testing evaluation techniques as well as the excavation of pits for geotechnical exploration and testing in order to evaluate the as-built soil stabilization methods. Non-destructive testing services provided on this project included ground penetrating radar scanning and relative elevation surveying. Other activities included the evaluation of the original concrete pavement design and assumptions, performance of a life cycle analysis, performance of service life calculations given the actual usage of the pavement, and review of construction related issues. CA also developed recommendations for the repair and remediation of the concrete pavement system.

By CA User 0 Comments

Seismic Analysis and Design Review of a Power Plant Chimney

A 460 ft. tall reinforced concrete chimney for a power plant was designed under strict loading parameters including the effects of seismic forces. CA was asked to review the design of the chimney to assure it had been designed for the appropriate loads including seismic, wind, and dead loads. CA performed a finite element analysis of the chimney to determine the in-service stresses experienced by the chimney for various load combinations. Furthermore, CA reviewed the original and as-built plans and drawings, original design calculations, and analyzed the design procedure. CA determined the appropriate design procedure and loading conditions and assessed the addition of structural fiber reinforced polymer reinforcement to the as-built structure to provide supplemental stability and capacity.

By CA User 0 Comments

Repair and Rehabilitation of a Post-Tensioned Parking Garage

A two story, cast-in-place post-tensioned concrete parking garage cut into the side of a slope provided a parking area and structural support for a major grocery store. The second floor of the parking garage was level with the surface parking area adjacent to and in front of the grocery store. Issues investigated were related to water intrusion, concrete cracking, foundation performance, retaining wing wall movement, loss of subgrade support, jointing, construction defects, moisture management, and performance of the post-tensioned beams.  These issues were investigated to determine any possible impacts on the long-term performance of the structure. CA performed, among other things, a detailed condition assessment of the structure, review of construction related documents, drawings, and plans, and a structural analysis and evaluation of the post-tensioned structure. CA successfully determined the causes of the concerns and developed recommendations for repair and rehabilitation of the structure to restore its performance.

By CA User 0 Comments

Concrete Rehabilitation with Fiber-Reinforced Composites at an Air Force Base

Kelly Air Force Base (KAFB), the oldest military airfield in the United States, is the home of the Air Logistics Center and the Air Force Electronic Security Command in San Antonio, Texas. The building housing the Air Force Electronic Security Command exhibited distress in the concrete flat slab which resulted in concerns regarding its performance and adequacy for its intended use. CA performed a building condition assessment, identified the cause of distress, and replicated the in-place conditions in a finite element model of the building. The results from the structural analysis were further used to locate the problem areas in the building and they were confirmed by comparing the model predicted distress to the observed distress in the structure. CA designed a fiber reinforced composite repair system for the rehabilitation of the concrete structure.

By CA User 0 Comments

Structural Evaluation and Testing of a Parking Structure

Work performed on a parking structure located in Plano, Texas, encompassed a two phase investigation. Phase I consisted of investigating the cause of cracking occurring in the precast, prestressed double tee beams which resulted in the repair or replacement of several double tees. The forensic structural engineering investigation included a condition assessment of the parking garage structure, evaluation of the double tees removed from the structure, sampling of the concrete, non-destructive testing, petrographic examination, and analytical testing. Phase II consisted of investigating the cause of distress in the architectural precast concrete elements by performing a condition assessment and evaluation of the architectural precast elements in-place. It involved determining the adequacy of the erection details, connections, and the overall structural integrity of the precast architectural members.  CA’s forensic consulting work on this project involved performing a structural analysis, sampling, testing, and petrographic examination of the concrete, the review of concrete production and construction practices, and the development of recommendations for rehabilitation and maintenance of the parking garage structure.

By CA User 0 Comments

Emmet Shelton Bridge Structural Analysis and Rehabilitation

CA performed a four phase investigation of an existing 1940’s composite steel and concrete bridge spanning the Colorado River in Austin, Texas. Phase I consisted of  full-scale instrumentation and load testing, including performing a preliminary structural analysis and providing  consulting engineering services related to the emergency transport of heavy loads across the bridge well in excess of the rated capacity of the structure. Phase II included a condition survey of the superstructure and substructure which involved photographic documentation of the existing structural conditions, testing of the existing concrete, underwater inspection of the bridge foundation, installation of strain gauge monitoring devices, and addressing safety issues regarding traffic. Phase III involved the continued monitoring of the in-service behavior of the bridge in addition to performing a life-cycle analysis of the structure in its present condition based on the field data obtained in Phase II. Phase IV consisted of the design of repairs for the superstructure and substructure and construction administration and inspection of the implementation of the rehabilitation.

By CA User 0 Comments

Concrete Finish Discoloration

The investigation consisted of determining the cause(s) of discoloration in the hard-troweled finished surface of the elevated structural slab in a high rise building. CA performed a visual inspection of the facility, extracted samples from the concrete surface, and performed a petrographic examination. The discolorations were found to be very shallow. The concrete samples did not indicate the presence of any deficiencies in the concrete requiring any further action other than the removal of the discoloration through very light polishing in order to restore consistency in the appearance of the finish of the elevated slab.

By CA User 0 Comments

Assessment of a Cast-In-Place Post-Tensioned Concrete Parking Garage

A four story, cast-in-place concrete parking garage consisting of an elevated pan-joist slab system framed by post-tensioned concrete beams provided a parking area and a structural frame foundation for a three story commercial office building. The elevated ramps for the parking garage exhibited distress in the form of full depth cracking in the elevated slabs parallel and adjacent to the post-tensioned beams and perpendicular to the longitudinal direction of the intermediate joists allowing for moisture migration and efflorescence to form on the underside of the elevated slab along the length of the cracks. CA performed, among other things, a detailed condition assessment of the structure, including crack maps of the entire parking structure, a review of drawings and plans, and a structural analysis of the post-tensioned beam and joist framing system accounting for their support and restraint conditions. CA determined the causes of the observed distress and developed recommendations for concrete crack repair and remediation of the reinforced concrete structure.

By CA User 0 Comments

ABIA Passenger Terminal

CA was retained by the City of Austin to perform a condition assessment of the precast parking garage structure, evaluate the design of canopies in the rental car area, and provide recommendations for the repair and rehabilitation of the parking garage and canopies, pedestrian bridges, elevated roadway, and entrance/exit ramps in the Austin – Bergstrom International Airport (ABIA) located in Austin Texas. The parking garage at the ABIA is a three-level precast concrete structure which encompasses approximately 1.2 million square feet. Distress areas in the parking garage structure included cracking, spalling, and deterioration of the joints. The structural steel canopies cover all parking garage spaces on the third floor rental car level. Distress in the canopies was observed in areas of the expansion joints, attachment to the metal roof deck, supporting members, base plate connections, and concrete columns in the aforementioned. Repair recommendations included the replacement and repositioning of bearing pads, repair of cracking and spalling, installing lateral bracing of supporting members, tightening base plate columns, and repairing the concrete columns, among others. CA designed the retrofit for the structural members and worked directly with the contractor during the rehabilitation of the structure.

Other Selected Airport Experience

Other airport-related projects include, among others, work performed on the runway pavement at the Denver International Airport, Puerto Rico’s Luis Muñoz Marín Int’l Airport, taxiway at Houston’s Hobby Airport, and several military installations.