Journal of Performance of Constructed Facilities

Tests on two-way reinforced concrete slab-column connections with simulated delamination are reported. The experimental results are compared with test results of companion specimens to investigate the effects of significant delamination on the punching and postpunching responses of the specimens, as well as the effects of structural integrity reinforcement on the postpunching behavior of delaminated specimens. The results are also compared with predictions of punching shear resistance and postpunching shear resistance predictions. Significant delamination of the top reinforcement caused decreases in prepunching stiffness, punching shear resistance, and postpunching shear resistance of the specimens. The provision of structural integrity reinforcement allowed for the development of a postpunching shear resisting mechanism, increasing the postpunching shear resistances and ultimate deflections.

An accident involving the collapse of a running tunnel along the Nanjing Metro (Jiangsu Province, P. R. China) occurred as the tunneling shield arrived at the receiving shaft. The brine freezing method was used for the recovery of the collapsed tunnel. During the recovery project, another collapse resulting in the leakage of water and sand occurred. By considering the tight construction schedule, the freezing method was also used for the second recovery. Liquid nitrogen freezing was adopted as the primary process and supplemented by brine freezing. On the basis of the real-time variation of the frozen soil temperature, which was obtained through an informatized construction system, this study analyzes the freezing effect at each construction stage of the second recovery and identifies the advantages of liquid nitrogen freezing over brine freezing. It also evaluates the safety and rationality of the freezing scheme. The successful completion of each construction stage and reconnection of the collapsed section of the metro tunnel are described. Compared with brine freezing, liquid nitrogen freezing is shown to have the advantages of faster cooling, lower temperature, and wider frozen range. The freezing construction scheme of the second recovery project was safe, but it should be more economical. To reduce the engineering cost, it is necessary to fully utilize the advantages of liquid nitrogen in other freezing projects.

The combined impact of the service life and relevant reliability level of structures on the financial and environmental aspects of infrastructure building has not yet been given full consideration. The decision of the client regarding the optimal service life and associated level of reliability is needed. A suitable approach is presented in the context of limit states associated with durability. The reliability assessment is effectively performed by employing stochastic methods. Predictive mathematical models for material degradation are utilized. Some user-friendly tools and numerical studies for concrete structures show how the necessary data about service life and reliability level can be gained; in this way good design practice in the construction industry and effective decision-making processes are supported. Two numerical examples are presented, as follows: (1) an analysis of initiation period with consideration given to the carbonation effect (a compromise between the service life and the reliability index is studied), and (2) an example of a concrete structure manufactured from concretes of different quality and exposed to chloride ion ingress.

Increasing overweight truck traffic, as evident by a rapid increase of permits issued for such traffic in Texas, tends to accelerate the deterioration of pavement structural integrity. However, it is less known to what degree buried utility facilities along and across the right-of-way are affected by these overweight loads, especially if these facilities are aged or placed under an exception to the Texas Utility Accommodation Rules (UAR). In this study, researchers evaluated the damage potential of buried pipe subjected to repeat overweight traffic loads. Based on a review of technical design and engineering requirements for utility accommodation in Texas, a large-scale laboratory test was conducted to investigate fatigue behavior of polyvinyl chloride (PVC) and concrete pipe. The result of both static and fatigue load tests indicated that pipe deformation in terms of vertical diameter reduction was less than 5% of pipe diameter, the maximum allowable value. However, fatigue damage was observed for the concrete pipe even though the deformation level was very minimal. A sensitivity analysis based on the finite-element method was conducted to validate the findings of the laboratory test. The study concludes that the current UAR appear adequate with respect to the likelihood of fatigue damage to buried pipes attributable to repeat overweight loads.

A high-rise building with pile-raft foundation suddenly experienced extraordinary settlements and seriously tilted after 6 years of use in Wenzhou, a city in southeastern China. Some investigations were conducted and several potential causal factors were analyzed to determine the cause of the distress. The results indicated that the inadequate bearing capacity of the pile foundation was the reason for the extraordinary settlement. Inappropriate structure type selection and structural arrangement made the building sensitive to earthquake-triggered loading and prone to tilt. Remedial measures were applied to address the causal factors identified. Because of the low bearing capacity of the pile foundation, unloading was first performed and then the pile foundation was strengthened using steel pipe piles driven by anchor bolts. To address the inappropriate structure type and arrangement, the building was retrofitted to resist earthquakes. Observation results showed that the remedial measures took effect and the settlement (and tilt) of the building was completely controlled.

A pedestrian suspension bridge over Walker Creek near Route 749 in Giles County, Virginia, partially collapsed in October of 2008, causing 10 people to fall into the creek below. The failure occurred when one of the anchors holding a suspension cable fractured. This paper presents the investigation of the failure, including a structural analysis of the bridge to determine cable forces, material property testing of the fractured anchor, laboratory testing of a different anchor from the bridge, and a simple strength evaluation of the anchor under combined axial force and moment. Based on the results of the study, it was concluded that the anchor should not have failed carrying the loads on the bridge on the day of failure. The anchor failed in brittle fracture because of a local defect in the material at the perimeter of a corrosion pit on the surface of the anchor hook. The structural analysis and laboratory testing indicated that the material around the defect was at yield before fracture initiation. The material flaws significantly influenced the bridge failure after yielding and inelastic deformation of the anchor material at the inside of the hook radius occurred.

The evaluation of a welded, steel girder bridge that once crossed the Rio Puerco River near Albuquerque, New Mexico, is presented in this study. Following 44 years of service, the bridge was scheduled for total replacement due to the poor condition of the structure. On May 18, 2011, the bridge girders collapsed due to lateral torsional buckling during removal of the concrete deck, resulting in a few injuries but luckily no loss of life. The buckling resistance of the compression flange of the steel girders was evaluated. Dead load and live load effects were determined from three-dimensional analyses. The results presented herein show that the deck removal procedure was not structurally sound and the compression-flange flexural capacity was exceeded in the exterior girder due to inadequate bracing, which initiated the bridge collapse. Following buckling of the exterior girder, load redistribution to the remaining girders resulted in demand versus capacity ratios exceeding 1, and ultimately progressive collapse of the entire bridge.

Based on analysis of a progressive collapse mechanism, this paper presents a simplified model for static analysis of progressive collapse response of RC beam-column substructures under midspan point loading. The proposed model expresses the load-deflection response directly, and it consists of three stages—beam mechanism stage, transient stage, and catenary mechanism stage. In the model, the influence of the span, the sectional dimension, and the reinforcement of the beam on progressive collapse behavior of substructures can be taken into account. The proposed model is validated by experimental results in literature. Last, progressive collapse-resisting capacity curves of substructures are established based on the energy conservation principle, which establishes a foundation for progressive collapse assessment of RC frame structures.

Departments of transportation are increasingly embracing pipe ramming for culvert installation under roadways due to its cost effectiveness and ability to mitigate problems associated with open-cut trenching. Despite the increase in use, little technical guidance is available for the engineering of pipe-ramming installations. This study presents the analysis of the performance of an instrumented 610-mm-diameter steel pipe installed using pipe ramming. Measurements include ground surface movement and dynamic force and velocity waveforms to obtain driving stresses, hammer-pipe energy transfer, and static and dynamic soil resistance during the installation. Ground movements are compared to existing settlement prediction models. Inverted normal probability distribution models commonly used in tunnel engineering were evaluated and were observed to capture the observed settlement close to the center of the pipe but did not accurately predict the observed transverse settlement profiles. The transfer of energy was observed to range from as low as 17–39% of the estimated hammer energy. Compressive stresses were observed to remain relatively constant over the penetration length observed and were well below the yield stress of the pipe. Soil resistance derived from wave equation analyses were compared to four pipe-jacking models to evaluate their accuracy and applicability for planning pipe-ramming installations. The jacking models bracketed the static soil resistance components of the wave analysis, indicating that the models may be adopted for pipe-ramming applications pending empirical modification.

Under a collapse scenario, the sudden loss of support causes a dynamic response that can amplify the internal forces in the members and lead to greater damage. This study considered a one-quarter scale, 2-bay, 2-story RC frame that was axially restrained at the beam locations. The frame was loaded with dead weights, and the support under the center column was kicked out to initiate the dynamic test. The results from four dynamic tests of a reinforced concrete frame with discontinuous reinforcement under various levels of applied load are presented. The fourth drop, with a load corresponding to 42% of the design ($1.2\times \mathrm{dead}\mathrm{load}+0.5\times \mathrm{live}$ load), did result in a catenary action range of response. A simple single degree of freedom (SDOF) analysis showed that there is a snap-through effect, i.e., a very fine tipping point at which the structure is pushed past the compressive arch or flexural range of response into the catenary action range of response. At this point, the loads in the structure increase significantly due to the dynamic effects.

In 2010, the Tennessee Department of Transportation (TDOT) launched a bridge rehabilitation project to rerate all truss bridges with gusset plate connections due to the federal mandate after the Minneapolis bridge collapse in 2005. One bridge that needed to be renovated was the Hurricane Bridge in Dekalb County, Tennessee. To provide a durable bridge deck and meet the latest highway loading specifications, TDOT used a Class L ternary (sand-lightweight ternary) mix instead of their standard Class D (normal weight nonternary) bridge deck mix. While placing a section of the deck, TDOT would cast cylinders to send to the University of Tennessee for rapid chloride penetration (RCP), surface resistivity (SR), and compressive strength testing. Previous RCP and SR testing of the TDOT Class D mix found that the mix provides poor to moderate chloride ion penetration resistance. Research reported herein supports the use of the TDOT Class L ternary mix as an alternative to the TDOT Class D mix in order to increase bridge deck durability. The results of the Class L ternary mix cylinder testing show a decrease in chloride ion penetration, an increase in surface resistivity, higher compressive strengths, and a higher correlation between SR and RCP than Class D cylinders.

Low-density polyethylene (PE) was grafted with maleic anhydride (MAH) in solution, which was proved by the infrared (IR) spectrum test result. The grafting ratio peaked at 3.3% as the grafting temperature maintained at 90°C. Compared with the PE-modified asphalt, approximately a 5°C increase of the softening point of the PE-MAH–modified asphalt was observed. Once the dosage of the PE-MAH was higher than 3%, the penetration index of the PE-MAH–modified asphalt was considerably enhanced, whereas its equivalent breaking point was declined radically. In addition, the elastic recovery test supports that the PE-MAH–modified asphalt exhibits a superior capacity of recovering deformation than PE-modified asphalt. The performance grade (PG) test results show that PE-MAH–modified asphalt is preferable to PE-modified asphalt both at high temperature and low temperature. The rutting test results of AC-13 verify that PE grafted with MAH contributes to the higher temperature stability and the lower displacement.

Performance of different cementitious repair materials is studied as part of an ongoing repair project on an existing reinforced concrete jetty in harsh environment of Persian Gulf. Concrete repair materials with different cementitious binders including ordinary portland cement, silica fume, and ground granulated blast furnace slag were tested. Different performance criteria such as mechanical properties, durability characteristics, and dimensional compatibility with substrate concrete were studied according to a proposed rational approach. It is concluded that a repair technique containing ternary pozzolanic materials has the best performance and could be proposed for marine environment.

In several northern regions around the world, concrete dams are subjected to severe seasonal temperature variations, with up to 75°C changes from summer to winter. Those variations contribute to the degradation of the stiffness, strength, and durability of concrete dams. Thermal stresses and related concrete cracking also need to be evaluated to ensure the structural stability of the dam and to define the initial conditions for unusual or extreme load combinations, such as floods and earthquakes. This paper presents finite-element modeling procedures for assessing the thermomechanical behaviors of concrete dams. The stress relaxation and mechanical properties that depend on the temperature of the concrete are first investigated by considering the thermomechanical responses of simple notched beam models. Heat transfer and thermomechanical analyses are then presented for a 31-m concrete gravity dam and a 214-m multiple arch dam located in Canada. It is shown that temperature-dependent material properties do not significantly affect the structural response of the dam. Oblique cracks present on the downstream face of the multiple arch dam are successfully reproduced by the proposed numerical model. Modeling of the related cracked arch flexibility using equivalent linear continuum concrete constitutive models is also discussed.

By analyzing the field data from nine metro-station pits with aspect ratios (AR) of pit length to width of 6.6–19.4 in Shanghai soft clay, this paper investigates the potential corner effects (i.e., the retaining walls near pit corners have stronger capabilities to resist deformation than those distant away as a product of spatial arching effects across the pit corners) of long and narrow multipropped metro station excavations. Contrary to the two-dimensional (2D) plane-strain assumption widely adopted in practice for analysis of a metro station excavation (i.e., deformations of the pit in which the displacements of all points along the longitudinal sides are assumed to be parallel to a given plane in the transverse direction and the values of these displacements do not depend on the distance perpendicular to the plane), seven out of the nine metro station pits exhibited apparent corner effects and only two showed plane-strain conditions. Because of the stiffening effects from the pit corners, the minimum wall deflections occurred near the pit corners and the maximum occurred near the middle span of the pits. The development of the maximum wall deflections along the longitudinal sides of the pits, which were normalized by the final excavation depths, can be bounded by two liner curves. Because of their narrow widths, the observed corner effects of the metro stations were less pronounced than that of a rectangular excavation with an AR of about 2.0. Distinctly different from the findings in literature for regular rectangular excavations with AR of 1.0–2.0, the variation of either the pit length-to-depth ratio or the pit length-to-width ratio hardly affected the corner effects of metro station pits. The derived graphical solutions accounting for the influence of pit lengths on corner stiffening effects can be used as references for future design and construction of a long and narrow multipropped pit in soft clays. The monitoring data regarding the adjacent building settlements demonstrate that the mobilized corner stiffening effects during excavation were helpful in constraining the ground deformation and protecting the structures or facilities in the proximity.

Reinforced concrete (RC) buildings having the adequate amount of structural wall area with a symmetrical arrangement have been proven to have a satisfactory seismic performance in past earthquakes. Properly constructed structural walls can even eliminate the poor seismic response of RC buildings due to the adverse effect of structural irregularities or deficiencies such as soft story, short column, insufficient confinement, poor detailing in beam-column joints, poor material quality, etc. The positive effect of structural walls was observed by comparing the performance of two RC buildings, which were affected by the May 19, 2011 Simav earthquake in Turkey. Although one of the buildings with no structural wall collapsed, the building with structural walls survived without any structural damage. Analytical models of the two buildings were developed to investigate the influence of structural walls on the seismic performance of RC buildings by conducting response history and pushover analyses. Results of detailed analyses of the two buildings indicated that the building with structural walls should respond better to strong ground motion, and this was confirmed by the relative behaviors of the two buildings.

This paper reports on a wide-ranging study conducted on the interim technical assessments (ITAs) drawn up for lawsuits over defective constructions in Tuscany, Italy, from 2000 to 2011. It provides a set of statistically significant data to highlight the impact of construction defects in buildings and evaluate their origins and the responsibilities of the technical personnel involved. The data have been classified according to various categories based on the type of damage encountered. Analysis of the most common types (in particular, water damage) and comparisons with the data from a similar survey carried out in 1990–1999 provide indications as to the critical aspects deserving of special attention, including building design and inspections during construction. Such analysis can provide useful information for assessing whether the quality of construction has kept pace with new knowledge and advances in technology.

A comprehensive test program was conducted on the compressive strength of concrete cores. The tests involved eight mixes of concrete. Because over 200 tests were conducted, it was possible to undertake an analysis of the concrete cores using the probabilistic treatment of strength. The present work reports a comparative study of alternative probabilistic models to describe the compressive strength of concrete cores. A large class of probability models including two-parameter Weibull, three-parameter Weibull, normal, lognormal, and gamma distributions were validated using test data. This information is useful in the theoretical description of concrete failure. Furthermore, the results were compared in terms of modified Kolmogorov-Smirnov, log-likelihood, and minimum chi-square criterion. The results suggested that none of the described probability methods are adequate for determining the variability of the compressive strength of concrete cores.

Following major earthquakes in the 1970s, 1980s, and 1990s, changes were made to the structural seismic design codes. Structures constructed prior to these revisions need to be evaluated for seismic vulnerability. The US-89 Overpass in Montpelier, Idaho, built in 1971, is the subject of this study. The current seismic design guides were used in conjunction with Open System for Earthquake Engineering Simulation (OpenSees), an advanced finite element computer modeling program, to perform nonlinear analyses of the bridge structure under four displacement time histories. The results show failure of the elements that restrain the lateral movement of the bridge deck. However, the lateral relative displacement between the superstructure and the top of the piers reach a maximum of 11.2 cm (4.4 in.), which is not enough to remove the superstructure from the 1.8 m (6 ft) wide seat. The work presented herein enhances seismic analysis capabilities for existing Idaho bridges and provides valuable information regarding this particular overpass.

A completed car park canopy collapsed shortly after its completion. The structural system of the car park canopy was a T steel structure of unequal cantilevers connected to the ground at the base with eight 25-mm anchor bolts. The collapse was a progressive one starting with the steel structure located at one end of the roof. An investigation of the causes of collapse was carried out. Before the collapse, the maximum tension acting on an anchor bolt was not more than 10% of the tensile strength of the bolt. This investigation shows that the use of incompatible bolts and nuts such as in the case reported lead to the total loss of the tension capacity of anchor bolts in 3 days.