Journal of Performance of Constructed Facilities

Forensic evaluations of residential structures often make use of relative elevation surveys of the floor slab. The objective for the analysis of these data is to estimate the postconstruction distortions which have occurred to the floor slab, in order to determine if such distortions might result from excessive movements of the supporting soils. However, such estimates are complicated by the findings of several recent studies that residential slab-on-grade floors exhibit substantial deviations from level at the time of construction, and by the expectation of some postconstruction movements in response to structural loads. In this study, commonly used methods were used to back-analyze relative elevation data from slabs with known distortions as a means to check the performance of these methods. The results strongly suggest that relative elevation surveys may be overemphasized in current practice, as (1) maximum elevation differences significantly overestimate distortions; (2) maximum slopes are quite insensitive to distortions; and (3) pattern recognition approaches are unreliable as an indicator that distortions have occurred.

This paper discusses applications of ASTM C 597 “Standard Test Method for Pulse Velocity Through Concrete” technique to field detection of damage to concrete in service and field quality assessment of cast-in-place concrete and masonry under construction. Four unique field investigation and validation studies are discussed in this paper. The first part includes field assessments of concrete members under construction with questionable quality. Case studies include detection of zones of high air content and low strength concrete in a cast-in-place, posttensioned structure and detection of voids and honeycombs in poorly consolidated cast-in-place beams. The third case study pertinent to construction involves detection of poorly consolidated collar joints in a masonry rehabilitation project. In addition to assessments during construction and rehabilitation, this paper also discusses assessment of damage to concrete structures in service. The case study included in the paper involves exposure to elevated temperatures during a fire at a precast, double tee concrete parking structure. Nondestructive evaluation (NDE) testing findings were validated by subsequent laboratory testing or selective demolition to confirm NDE findings. This paper should be of value to practicing engineers interested in application of pulse velocity testing technique in field assessments similar to ones discussed. This paper should also be of value to researchers interested in applicability of pulse velocity to research concerning properties of concrete subjected to the damage mechanisms associated with elevated temperatures.

Mine spoil valley fills are a by-product of mountaintop removal mining in the Appalachian coal mining region of the United States. These fills often result in large expanses of relatively flat land covering thousands of acres, which can be used for commercial or industrial development. However, this material is susceptible to damaging settlement, and highly publicized failures of structures built on mine spoil fills have led to reluctance on the part of investors to develop these areas. A key settlement mechanism in mine spoil is water infiltration. Percolating water slakes the shaly, angular spoil material at interparticle stress points, leading to excessive deformation and settlement. A lumber processing facility in Hazard, Ky., is an example of a structure that sustained serious damage as a result of settlement caused by water infiltration. A forensic site investigation of the facility revealed that excavation of existing surface mine spoil beneath the building footprint removed the low-permeability crust that forms on the top of mature mine spoil fill deposits. The removal of the crust allowed the infiltration of surface water. This, coupled with the unique configuration of the storm water drainage system at the facility and surface water drainage toward the building, led to differential settlement up to 1:120 (vertical:horizontal) and angular distortion up to 1:150 over a period of several months. Foundation underpinning was performed to remedy the situation. For future development on mine spoil sites, recommended mitigating measures include presaturation of the mine spoil, design of drainage systems to adequately convey surface water away from the building, and use of geosynthetic barrier layers to prevent infiltration of surface water into the mine spoil beneath the structure.

This study assesses performance objectives defined in the Turkish Earthquake Code (TEC) in order to make a realistic evaluation related to heavy damage and collapse reasons of reinforced concrete (RC) buildings that experienced severe earthquakes in Turkey. A series of three-dimensional RC buildings with different characteristics and representing low-rise structures damaged and collapsed in the earthquake areas is designed according to Turkish codes (Turkish Design Standards and Turkish Earthquake Code). Pushover analyses are carried out to determine nonlinear behavior of the buildings under earthquake loads. Building performances are determined by using the displacement coefficients method, which is a commonly used nonlinear static evaluation procedure for different seismic hazard levels defined in the TEC. The stipulated performance objectives in the TEC are checked in terms of plastic rotations and maximum story drift. From the results of this research, it can be concluded that low-rise RC buildings designed according to Turkish codes sufficiently provide for the performance objectives stipulated in the TEC. Reasons for the heavy damages and collapses of RC buildings during severe earthquakes are explained by commonly occurring themes (i.e., project errors, poor quality of construction, modifications of buildings, etc.).

This paper presents details of a large field trial and some observations conducted to evaluate the practical efficiencies of geosynthetically reinforced asphalt pavements in Shanxi Province, China. Three glass-fiber grids (LB2000 II, TGG-8080, GGA 2021), one plastic grid (Tensar AR1), two geotextiles (nonwoven needle-punched and nonwoven heat-bonded), and one geocomposite (Tensar AR-G) application were selected for evaluation. These geosynthetics were installed in the interface between new asphalt pavement layers (APL) and new cement-stabilized gravel–sand base courses coated by emulsified asphalt or within new APL in the reconstruction of asphalt pavement sections (Program I), or in the interface between old APL and new overlay layers in the asphalt overlay pavement sections (Program II). In each program, reinforced sections with different geosynthetics were compared with each other and with nonreinforced sections to determine relative performance. Inspections after construction showed that the integrated damage ratio and deflection in the pavement sections reinforced with glass–fiber grids were less than other pavement sections. Furthermore, after about $4\text{years}$ of service, glass-fiber grids were dug out and no breaking and node movement were discovered. Nevertheless, observations indicated that geosynthetics may not be effective, if bearing capacity of the base course/subgrade is inadequate, or if the overlay thickness is too thin, or if preconstruction repair of distressed old pavement is incomplete.

An innovative bridge construction utilizing on-site posttensioned precast concrete beams that are compressed together with full depth grouted shear keys and transverse posttensioning is the subject of this paper. In particular, the performance of the shear keys with regard to load transfer and water tightness constitutes the main issues of investigation. This paper presents the results of a live load testing program and associated finite-element analysis results of the as-built bridge. Live truck load test results help provide insights on the lateral (transverse direction) load distribution characteristics among the interconnected beams. The measured lateral distribution of the applied truck load among adjacent beams showed that the load was transferred primarily to the beams close to the truck load position, validating the effectiveness of the shear key details in transporting loads.

This paper describes a successful failure analysis to determine the causes of loss of backfill sand from a mechanically stabilized earth (MSE) wall, and cracks on the concrete approach slabs on top of it. The Texas Department of Transportation was concerned that the cracks on the approach slabs may be related to the excessive loss of backfill from behind the MSE walls, and that the embankment structure may be unsafe due to potential voids under the concrete slab. Several cubic meters of sugar sand had washed out of the wall and deposited adjacent to the paneled walls. A series of destructive and nondestructive tests were carried out to determine the causes of the problems. It was found that the cracking of the approach slab and the loss of backfill were unrelated. Suggestions for resolving both problems were made based on this study.

River bridges and related infrastructural elements need to be monitored and inspected periodically for deterioration and loss of function due to aging, adverse hydraulic conditions, and chemical attacks. Necessary protective works and related actions should then be implemented to increase safety. Types of items to be inspected would be categorized as structural, geotechnical, hydraulic, and structural material conditions. Requirements for periodic inspections and the ways of handling these activities were discussed within the framework of the aforementioned aspects. Since each bridge authority has its own inspection grading system according to variations in local conditions and the socioeconomic status of the country, a common core methodology should be implemented such that comparisons with different case studies are meaningful. The aim of this study is the renovation of the current inspection system in Turkey, in order to implement it primarily for saving human life, as well as promoting Turkey’s economy, labor, and manpower. An algorithm, based on evaluating components of the main body, earth-retaining facilities, and serviceability, as well as hydraulic aspects, is proposed. This renovation enables the identification of rank-based prioritization of events. The evaluation and interpretation steps were displayed with the help of a case study.

A nationwide survey revealed 14 states having bridges comprised of precast, nonprestressed, concrete channel beams. Currently, the Arkansas State Highway and Transportation Department (AHTD) bridge inventory includes approximately 389 in-service bridges using $5.79\mathrm{m}$ precast channel beams that were constructed using 1952 AHTD bridge details. Results from a statewide inspection of these bridges conducted by the writers revealed bridges with extensive concrete longitudinal cracking at the flexural reinforcing steel level and exposed reinforcing steel. Approximately 2,000 beams in 95 precast concrete channel beam bridges were inspected during a statewide investigation; longitudinal cracking at the reinforcing steel level was observed in 60.4% of the beams and exposed flexural reinforcement in 21.2%. A combination of flexure cracking from the live-load overloads and the presence of moisture has led to this high level of beam deterioration. The source of this moisture is humidity and water seepage at joints between adjacent beams. This paper examines the causes of longitudinal cracking deterioration by examining the influences of water permeation and humidity on the corrosion of flexural reinforcement in precast concrete channel beams.

The study concerns bridge collapses focusing on metal structures. It is based on literature and news research, due to the lack of extensive compendiums of this unpleasing but important topic. At first, a short overview of the occidental history of metal bridges is given presenting the historic context for the described incidents. It is followed by a classification of the most common causes of bridge failure, which include structural and design deficiencies, corrosion, construction and supervision mistakes, accidental overload and impact, scour, lack of maintenance or inspection, and force majeure. Some significant historic examples are described. Changes and investigations initiated by the described cases are also mentioned. The work concludes that without the disaster that represents each bridge collapse, we would have neither the structural behavior knowledge nor the relatively high safety of today.