Strain monitoring system for steel and concrete structures

Cheilakou, Eleni; Tsopelas, N.; Anastasopoulos, Athanasios; Kourousis, D; Rychkov, Dmitry; Gerhard, Reimund; Frankenstein, B.; Amditis, Angelos; Damigos, Yannis; Bouklas, C.

doi:10.1016/j.prostr.2018.09.005

Cited by 12 publications

(4 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Each sample was allowed to cool down for seven days for observing the capacity of the different cements (SAC and OPC) to recover the strength lost after being exposure to 100 °C, 200 °C and 300 °C. The samples were then equipped on their surface with a BQ120-80AA resistance 120.3 ± 0.1 gauge factor 2.20 ± 1 % lot no.1901.01×12W4SB grade "A" from China AVIC Electric Instrument Co., Ltd. [15,16] as shown in Figure 2 to separately record with the aid of the DH3818Y static strain tester [17,18] the flexural stress-strain of each sample during the flexural testing application loads as shown in Figure 3. The ultimate testing machine (UTM) with an adequate capacity and with a layer of two steel skates of 38 mm was used, on which, the concrete samples were supported.…”

Section: Experimental Set-up and Test Programmementioning

confidence: 99%

Strengths of Sulfoaluminate Cement Concrete and Ordinary Portland Cement Concrete After Exposure to High Temperatures

Tchekwagep¹

2020

Ceramics - Silikaty

View full text Add to dashboard Cite

The use of SAC (sulfoaluminate cement) has been increasing in the constructions of diverse buildings with some close to reactors, which are often exposed to high temperatures in China. This study compares the flexural strength, compressive strength, crack load, mass weight loss, porosity, and flexural stress--strain of the sulfoaluminate cement concrete (SACC) to that of ordinary Portland cement concrete (OPCC) after both are exposed to high temperatures. The results show that the samples of SACC show a rapid decrease in the flexural strength, crack load, and compressive strength after heating, and, thus, cannot be repaired, but should be demolished. Samples made with OPCC can be repaired because the structural integrity remains acceptable after heating. 56 % SACC is < half of its initial strength after heating to 200 °C while OPCC remains at > 90 % of its compressive strength after heating at 200 °C, and retains 80 % of its compressive strength when heated to 300 °C. SACC initially had a higher flexural strength and consequently a higher crack load; therefore, it performed better than the OPCC in terms of the load carrying capacity of the structure. Also, the OPCC had a constant decrease in the strength, compared to the SACC which did not. However, the OPCC has a better resilience strength rating as the temperatures increase than the SACC one because testing revealed a very rapid decrease in the strength after exposure to 100 °C, 200 °C, and 300 °C. The results agree on the better firm structure uniformity and density of the SACC at an ambient temperature (20 °C) compared to the OPCC. The severe deterioration (micro-crack) inside both concretes, revealed by the longer transmitting time and the small amplitude values of the waves, indicated the effective negative impact which is no longer demonstrated when the extreme temperature has a larger effect on the concrete made with SAC, therefore, the other results highlighted the rapid decrease in the strength of the SACC compared to that of the OPCC.

show abstract

Section: Experimental Set-up and Test Programmementioning

confidence: 99%

Strengths of Sulfoaluminate Cement Concrete and Ordinary Portland Cement Concrete After Exposure to High Temperatures

Tchekwagep¹

2020

Ceramics - Silikaty

View full text Add to dashboard Cite

show abstract

“…However, ageing, deterioration and extreme events threaten these key assets, resulting in economically damaging bridge closures or even collapses [1]. Consequently, many different bridge structural health monitoring (BSHM) approaches have been proposed, some using strain [2], displacement [3], vibration [4] or acceleration [5] in order to detect damage or deterioration in the bridge response. Recently, rotation-based BSHM has been shown to offer a more practical approach for sensing short to medium bridge deflections under loading [6].…”

Section: Introductionmentioning

confidence: 99%

Detecting Vehicle Loading Events in Bridge Rotation Data Measured with Multi-Axial Accelerometers

Ferguson

Woods

Hester

2022

Sensors

View full text Add to dashboard Cite

Structural Health Monitoring (SHM) is critical in the observation and analysis of our national infrastructure of bridges. Due to the ease of measuring bridge rotation, bridge SHM using rotation measurements is becoming more popular, as even a single DC accelerometer placed at each end of span can accurately capture bridge deformations. Event detection methods for SHM typically entail additional instrumentation, such as strain gauges or continuously recording video cameras, and thus the additional cost limits their utility in resource-constrained environments and for wider deployment. Herein, we present a more cost-effective event detection method which exploits the existing bridge rotation instrumentation (tri-axial MEMS accelerometers) to also act as a trigger for subsequent stages of the SHM system and thus obviates the need for additional vehicle detection equipment. We show how the generalised variance over a short sliding window can be used to robustly discriminate individual vehicle loading events, both in time and magnitude, from raw acceleration data. Numerical simulation results examine the operation of the event detector under varying operating conditions, including vehicle types and sensor locations. The method’s application is demonstrated for two case studies involving in-service bridges experiencing live free-flow traffic. An initial implementation on a Raspberry Pi Zero 2 shows that the proposed functionality can be realised in less than 400 ARM A32 instructions with a latency of 47 microseconds.

show abstract

“…Современные высотные здания представляют собой сложные пространственные системы, состоящие из различных элементов и соединений, параметры (жесткость и т.п.) которых изменяются в процессе нагружения [15]. При мониторинге следует рассматривать весь комплекс статических и динамических воздействий, приводящих к изменению характеристик состояния: изменение жесткости соединений элементов, изменение физических свойств материалов, а также возможно изменение форм и размеров.…”

Section: Introductionunclassified

“…Modern high-rise buildings are complex spatial systems consisting of various elements and connections, the parameters (stiffness, etc.) of which change in the course of loading [15]. The whole range of static and dynamic influences leading to the change of the condition characteristics should be considered during the monitoring: changes in the stiffness of structural connections, changes in the physical properties of ma- Fig.…”

Section: Introductionmentioning

confidence: 99%

Monitoring system of high-rise buildings, determined from the nature of the curvature of the elastic line of vertical elements

Plotnikov

Ivanov

2019

Stroitel’stvo: nauka i obrazovanie

View full text Add to dashboard Cite

Introduction. Issues arising from the automatic monitoring of high-rise buildings are considered. One of such issues is the necessity of minimizing the number of sensors when taking the operational patterns of such load-bearing systems. The method of sensor placement in high-rise buildings is described. Materials and methods. Different structural systems of high-rise buildings have common dependencies of longitudinal axis deformation on rigidity of vertical and horizontal load-bearing elements. Calculation of deformations from static wind load, comparison of data obtained by manual and computer calculation, and also comparison of static wind load with the wind load pulsation component are performed. Results. From the analysis of the extrema of the deformation function of the building vertical axis with the horizontal plane of the floor structure preserved, the main typical monitoring points necessary to minimize the number of sensors in high-rise buildings were determined. Based on the typical breaking points, the required number of sensors located 1/4 of the building height away from each other and the range of measured values of deformations that occur during operation were determined. Conclusions. For automatic (constant) monitoring of high-rise buildings, it is advisable to use a complex integrated method of measuring deformations of vertical load-bearing structures, frequencies and amplitudes of oscillations, and rotation angles. According to the general design theory of high-rise buildings and computer calculation models, the most efficient placement of engineering structure monitoring sensors is when they are evenly covering the perimeter of each floor and the entire height of the building. Measurements should be carried out following the outlines of the floor structures on stories located 1/4 of the building height away from each other, as well as on the stiffening core to control the integrity of floor structures and their connection to the stiffness core.

show abstract

Strain monitoring system for steel and concrete structures

Cited by 12 publications

References 2 publications

Strengths of Sulfoaluminate Cement Concrete and Ordinary Portland Cement Concrete After Exposure to High Temperatures

Strengths of Sulfoaluminate Cement Concrete and Ordinary Portland Cement Concrete After Exposure to High Temperatures

Detecting Vehicle Loading Events in Bridge Rotation Data Measured with Multi-Axial Accelerometers

Monitoring system of high-rise buildings, determined from the nature of the curvature of the elastic line of vertical elements

Contact Info

Product

Resources

About