Ozgur Kurc

Providing Guidance for Evacuation during an Emergency Based on a Real-Time Damage and Vulnerability Assessment of Facilities

Following a disaster or an emergency situation (e.g., earthquake,) in a facility, it is crucial for emergency response teams to rapidly access navigation information of the facility, its contents and the final status of the facility (e.g., damages and vulnerable locations). However, in the current practice, accessing these information items is time-consuming and the accessed information is incomplete, since there are multiple sources of information that are mostly disorganized. This study proposes a Building Information Model (BIM) based approach integrated with sensors to provide the damage and vulnerability information of the facility for efficient response and for safe evacuation of the facility. The proposed framework integrates navigation algorithms, a vulnerability assessment approach and the status information obtained from various sensors that are strategically deployed inside the facility. This framework will be used for guiding the occupants and rescue teams through safe locations in a facility during evacuation.

Wireless Sensing in Complex Electromagnetic Media: Construction Materials and Structural Monitoring

In this paper, wireless sensing in the presence of complex electromagnetic media created by combinations of reinforcing bars and concrete is investigated. The wireless displacement sensing system, primarily designed for use in structural health monitoring (SHM), is composed of a comb-like nested split-ring resonator (NSRR) probe and a transceiver antenna. Although each complex medium scenario is predicted to have a detrimental effect on sensing in principle, it is demonstrated that the proposed sensor geometry is able to operate fairly well in all scenarios except one. In these scenarios that mimic real-life SHM, it is shown that this sensor exhibits a high displacement resolution of 1 μm, a good sensitivity of 7 MHz/mm in average, and a high dynamic range extending over 20 mm. For the most disruptive scenario of placing concrete immediately behind NSRR, a solution based on employing a separator behind the probe is proposed to overcome the handicaps introduced by the medium. In order to obtain a one-to-one mapping from the measured frequency shift to the displacement, a numerical fit is proposed and used. The effects of several complex medium scenarios on this fit are discussed. These results indicate that the proposed sensing scheme works well in real-life SHM applications.

Wireless Measurement of Elastic and Plastic Deformation by a Metamaterial-Based Sensor

We report remote strain and displacement measurement during elastic and plastic deformation using a metamaterial-based wireless and passive sensor. The sensor is made of a comb-like nested split ring resonator (NSRR) probe operating in the near-field of an antenna, which functions as both the transmitter and the receiver. The NSRR probe is fixed on a standard steel reinforcing bar (rebar), and its frequency response is monitored telemetrically by a network analyzer connected to the antenna across the whole stress-strain curve. This wireless measurement includes both the elastic and plastic region deformation together for the first time, where wired technologies, like strain gauges, typically fail to capture. The experiments are further repeated in the presence of a concrete block between the antenna and the probe, and it is shown that the sensing system is capable of functioning through the concrete. The comparison of the wireless sensor measurement with those undertaken using strain gauges and extensometers reveals that the sensor is able to measure both the average strain and the relative displacement on the rebar as a result of the applied force in a considerably accurate way. The performance of the sensor is tested for different types of misalignments that can possibly occur due to the acting force. These results indicate that the metamaterial-based sensor holds great promise for its accurate, robust and wireless measurement of the elastic and plastic deformation of a rebar, providing beneficial information for remote structural health monitoring and post-earthquake damage assessment.

Pseudo Dynamic Testing of an RC Frame Retrofitted with Chevron Braces

Two-story three-bay reinforced concrete frames with and without chevron brace was tested using pseudo dynamic test method. The chevron braces were implemented to the interior span of the RC frame. Chevron-braced frame was observed to be effective to control inter-story drift demands. Based on the observed damage state and dynamic response of the test frames, performance states were discussed for different scales of Duzce ground motions. The test results were compared with the results of the nonlinear time history analysis. The analysis results were capable of estimating the base shear capacity and displacement demands with a reasonable accuracy.

A Wireless Passive Sensing System for Displacement/Strain Measurement in Reinforced Concrete Members.

In this study, we show a wireless passive sensing system embedded in a reinforced concrete member successfully being employed for the measurement of relative displacement and strain in a simply supported beam experiment. The system utilizes electromagnetic coupling between the transceiver antenna located outside the beam, and the sensing probes placed on the reinforcing bar (rebar) surface inside the beam. The probes were designed in the form of a nested split-ring resonator, a metamaterial-based structure chosen for its compact size and high sensitivity/resolution, which is at µm/microstrains level. Experiments were performed in both the elastic and plastic deformation cases of steel rebars, and the sensing system was demonstrated to acquire telemetric data in both cases. The wireless measurement results from multiple probes are compared with the data obtained from the strain gages, and an excellent agreement is observed. A discrete time measurement where the system records data at different force levels is also shown. Practical issues regarding the placement of the sensors and accurate recording of data are discussed. The proposed sensing technology is demonstrated to be a good candidate for wireless structural health monitoring (SHM) of reinforced concrete members by its high sensitivity and wide dynamic range.

Building-Information-Modeling–Based Earthquake Damage Assessment for Reinforced Concrete Walls

AbstractEngineering analysis to quantify the effects of earthquake forces on the structural strength of components requires determining the damage mode and severity of the components. The analysis requires strength computations and visual damage assessments, which are information intensive, potentially error-prone, and slow. This study develops a building-information-modeling (BIM) based approach to support the engineering analysis of reinforced concrete structures. In the proposed approach, the damage information is represented along with the geometric, topological, and structural information. Transformation and reasoning mechanisms are proposed to utilize the information contained in the BIM to perform strength analysis and visual assessment tasks. The approach is validated on a case study building, which contains 42 damaged piers and spandrels.

Characterization of Laser Scanners for Detecting Cracks for Post-Earthquake Damage Inspection

Objective, accurate, and fast assessment of damage to buildings after an earthquake is crucial for timely remediation of material losses and safety of occupants of buildings. Laser scanners are promising sensors for collecting geometrical data regarding the damaged states of buildings, as they are able to provide high coverage and accuracy at long ranges. Yet, we have limited knowledge on the performance of laser scanners for detecting earthquake damage, and requirements of such data collection. This paper focuses on characterizing the performance of laser scanners for detecting thin cracks for damage assessment of reinforced concrete frames. We identified a series of crack parameters based on the state-of-the-art damage assessment codes and standards. Similarly, we identified parameters, which affect the performance of laser scanners for detecting cracks, based on prior research in this area. We studied the width, depth, and orientation of cracks; sampling interval of the scanner, and the range of the laser beam from the surface. Effects of these parameters on the detection of the minimum crack size were determined in an experimental setting. An automated algorithm was used to analyze the data. The results show that it is possible to detect as small as ~1mm cracks.

Information Requirements for Design and Detailing of Reinforced Concrete Frames in Multiuser Environments

AbstractThe design and detailing of reinforced concrete frames is a complex process that requires intensive real-time information exchange between various design tasks. The monolithic behavior of concrete, differences in the geometric representation of structural members during the analysis and design stages, and design code requirements throughout the process add new dimensions to the problem. Additionally, especially in large projects, reinforced concrete structures are designed and detailed by several engineers simultaneously. These complexities can be resolved and the overall quality of the design can be improved by identifying information requirements for managing the design information between the design and detailing tasks and thus between structural engineers. In this paper, requirements for managing information for multiuser design and detailing of reinforced concrete frames are identified and a prototype information model has been implemented based on existing literature. The means of performing...

Finite Element Modeling of a Reinforced Concrete Frame with Masonry Infill and Mesh Reinforced Mortar Subjected to Earthquake Loading

Failures of unreinforced masonry infill walls commonly occur during seismic events. One method of preventing such failures is the use of externally applied mesh reinforced mortar (MRM). This paper presents a finite element (FE) modeling scheme combining smeared crack and interface elements to simulate the seismic response of RC frames with hollow clay tile (HCT) infill and RC frames with HCT infill and MRM. The models can capture cracking patterns, timing of damages, and force-displacement behavior of the frames. A study modeling the plastering mortar with overlay elements and a transformed section approach suggests the latter gives more realistic predictions for initial stiffness and drift at peak strength. Parametric studies on the influence of dowel area and the placement of dowels indicate that there are diminishing returns in increasing the dowel area and that the connections must be present on both the top and bottom of the infill walls to be effective.

Application of Mesh Reinforced Mortar for Performance Enhancement of Hollow Clay Tile Infill Walls

The use of mesh reinforcement with mortar on existing brick infill walls of reinforced concrete (RC) frames is a recommended seismic strengthening procedure in the Turkish Seismic Code (2007). The premise of the method lies in its ease of application and success in eliminating the out-of-plane failure of existing infill walls. The performance of the mesh reinforced mortar (MRM) application was investigated by pseudo-dynamic (PsD) and cyclic testing. A three-story-three-bay 1:2 scale RC frame with hollow clay tile (HCT) infills in the middle bay was first tested using a continuous pseudo-dynamic test method for three synthetic ground motions compatible with the Duzce city center response spectrum. The test specimen was code complaint. No significant structural damage besides some cracking in the boundary columns was observed but the infill walls almost collapsed. After removing the infill walls of the central bay, a new HCT wall strengthened with MRM was built and the rehabilitated frame was retested under a second series of PsD and reversed cyclic loading schemes. This Chapter reports the findings of the experimental study by placing special emphasis on the seismic response of the code compliant test frame.