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Base isolation applications are becoming popular in the seismic design of resilient structures and infrastructures. Even though the response of the bearings is widely studied under cyclic displacements, limited information is available for bearing response under sustained lateral loads. These types of loads can develop sustained lateral displacement in the bearing. During the holding time under sustained lateral displacement, the creep or stress relaxation may significantly change the properties of the bearings and may affect the response in the reloading stage. This research paper aims at assessing the influence of short-term lateral creep on the hysteretic response of rubber bearings, and ball rubber bearings. To this end, experimental testing on different elastomeric bearings under imposed lateral displacement is performed. For each device, the lateral response is measured, and the advantages and disadvantages are discussed in terms of strength, stiffness, energy dissipation and equivalent damping. The loss of load under sustained lateral displacement is experimentally assessed and the effects of creep in the design procedure of a base isolated system are discussed. [ABSTRACT FROM AUTHOR]

Safety of a highway infrastructure system depends very much on the proper maintenance of bridges. The level of required maintenance is, typically, determined through a series of regular field inspections with the guidance of safety-economy trade-off. In Turkey, bridge maintenance, repair, and rehabilitation are currently performed on an as-needed basis. Time-dependent reliability analysis cannot be utilized for Turkish bridges for the time being since the majority of the bridges are either not regularly inspected or not inspected at all. The purpose of this paper is to propose a simple method to assess the remaining service life of a bridge by defining a relationship between its current condition rating and its age by evaluating a set of bridges at different ages. In a case study, 28 bridges were inspected for the first time to assess the average life expectancy. The average life of a bridge was predicted to be 80 years, and for this set of bridges, the main body components were found to deteriorate more than earth retaining and serviceability components. DOI: 10.1061/(ASCE)0887-3828(2008)22:2(108) CE Database subject headings: Bridges, highway; Deterioration; Inspection; Concrete; Steel; Service life; Serviceability.

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. DOI: 10.1061/(ASCE)0887-3828(2007)21:5(382) CE Database subject headings: Bridges; Inspection; Hydraulics; Maintenance; Scour; Rehabilitation.

Bridge collapses in Turkey have not been the subject of any comprehensive study so far. Investigations are often kept confidential for various reasons. As a result, most of the time only limited information can be found about these collapses with some exceptions such as the 1999 Arifiye Bridge collapse due to seismic event and the 2012 Çaycuma bridge collapse due to pier scour. Both resulted in fatalities, which drew public awareness from the first day. The focus of this paper is to identify the causes of bridge collapses and to assess the possible prevention measures based on lessons learned. In this scope, for the first time in Turkey various reported bridge collapses were gathered in a database mostly occurring between the years of 2000 and 2019. The study of over 80 bridges that experienced failures revealed that for road bridges hydraulic events and for pedestrian bridges vehicle collisions were the main causes. Bridge engineering in Turkey is briefly discussed to provide better understanding of the countries' conditions. A section is also included to mention some significant historical bridges whose design has helped them to withstand the conditions were still struggling to address in the 20th century. [ABSTRACT FROM AUTHOR]

Over the past years, a remarkable number of bridges have been collapsed or failed worldwide, underlying the growing importance of condition assessment of bridge structures within the context of health monitoring of structures and their life cycles become important to prevent such events. If utilised correctly, advanced Non-Destructive Techniques (NDTs) have proved to be effective in detecting imperfections such as bridge deck delamination, crack formation, and rebar corrosion. This paper presents the benefits of using Augmented Reality (AR) technology, applied combined, with visual inspection, Ground Penetrating Radar (GPR), Laser Distance Sensors (LDS), Infrared Thermography (IRT), and Telescopic Camera (TC). Using this approach, a bridge was investigated for weaknesses such as cracks and rebar corrosion. The methodology implemented in this paper can enhance structural engineers and/or asset manager's decision making, related to applying advanced NDT to dynamically affected bridges. [ABSTRACT FROM AUTHOR]

The safety of cable‐supported bridges primarily depends on cable design, proper tensioning during construction, and regular maintenance. Over the past decade, numerous cable‐supported bridges have faced various issues, including aging, poor tensioning practices, coping with heavy traffic loads, insufficient maintenance, and exposure to accidents or extreme conditions. Despite these challenges, these structures often withstand such problems due to the inclusion of redundancy and alternative load paths in their design. Detecting anomalies in bridge monitoring data can aid in identifying potential issues. Typically, only specific cables are monitored in a cable‐supported bridge monitoring system. The conditions of non‐monitored cables are usually estimated based on the data from adjacent cable sensors. The structural response of the tower and the deck can also be indirectly estimated. This research aims to present a methodology for detecting anomalies in structural responses following extreme events. It is crucial to differentiate temporary changes in cable measurements caused by expected seasonal temperature fluctuations, regular winds, and normal traffic patterns from permanent changes resulting from extreme events. Additionally, one must consider that a permanent change in measurements might also occur due to sensor loss after an extreme event. The paper will discuss tools to form a detection that can identify whether the source of change is due to a real extreme event or not. [ABSTRACT FROM AUTHOR]

Bridges in Turkey have been designed using a modified version of AASHTO Load Factor Design Specifications. In this paper, a new design spectrum is being analysed to address the characteristics of the Turkish earthquake records. The main contribution of this study is to suggest a mean Turkish site-dependent response spectra especially for the constant velocity region by analysing a number of Turkish earthquake records. The findings are compared to the two different design spectra of AASHTO. The mean site-dependent response spectra normalised with the peak ground accelerations are analysed for certain soil conditions and for a given range of moment magnitude values. The mean site-dependent response spectra corresponding to the largest moment magnitude range is observed to lie above the design spectra for periods larger than 1.0 s. Response spectrum analyses and time history analyses are performed on selected bridges using AASHTO design spectra and the mean site-dependent response spectra to observe the differences in corresponding structural responses. Results from analyses indicate that design spectrum is conservative for small to moderate moment magnitude levels. However, for the largest moment magnitude range considered, structural responses from mean site-dependent spectra are higher than those obtained from the design spectra. [ABSTRACT FROM AUTHOR]

SUMMARY New types of fiber-reinforced rubber-based seismic isolators have been a research interest for a number of engineers in the past decade. These new types of isolators can have similar seismic performances compared with the conventional ones. In most of the previous researches, the fiber-reinforced rubber-based isolators is usually manufactured with placing fiber sheets between precut rubber layers with the use of a bonding agent. This research differs from the previous researches in terms of manufacturing process, use of fiber mesh instead of fiber sheets, and use of lead in the core for some of the bearings. The aim of this research is to provide comparisons in fundamental seismic response properties of the new type of fiber mesh reinforced isolators and conventional isolators. In this scope, four pairs of fiber mesh reinforced elastomeric bearings and four pairs of steel-reinforced elastomeric bearings are subjected to various levels of compression stresses and cyclic shear strains under constant vertical pressure. The tested types of isolators are fiber mesh reinforced elastomeric bearing, fiber mesh reinforced elastomeric bearing with lead core, steel-reinforced elastomeric bearings, and steel-reinforced elastomeric bearings with lead core. In this research, steel-reinforced bearings are called conventional isolators. The major advantage for fiber mesh reinforced bearings observed during the tests is that these isolators can develop a considerable low horizontal stiffness compared with the conventional isolators. The damping characteristics of the new and conventional types are similar to each other. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article discusses the Seismic Isolation Methods and Practices Symposium of the Turkish Group Members of the International Association for Bridge and Structural Engineering (IABSE) that was held in Ankara, Turkey from February 28, 2013 to March 1, 2013.