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1 – 10 of over 14000In effort to understand and reduce flood consequences more effectively and strategically, flood risk assessment has been a cornerstone of a long-term flood management. One…
Abstract
In effort to understand and reduce flood consequences more effectively and strategically, flood risk assessment has been a cornerstone of a long-term flood management. One component of flood risk assessment is the estimation of a range of possible damage to an area exposed to flooding, that is, the vulnerability curve. The vulnerability curve can be depicted by a stage–damage relationship. This study attempts to investigate how vulnerability to flooding can be quantitatively assessed using a micro-scale approach in Malaysia’s vulnerable areas. A residential area in Kota Bharu was chosen as the case study area. Depth–damage relationships from a multiple regression function of Department of Irrigation and Drainage Malaysia and spatial variability of residential buildings were used for the micro-scale assessment. Final estimates of expected annual damage were then calculated for each building type at 1-, 3- and 5-day flood durations. Results show that the methodology adopted is feasible to be applied for local-scale assessment flood risk assessment in Malaysia. The results also suggest that applying the methodology is possible when given wider availability of resources and information. This is particularly important for a robust end-to-end flood risk assessment for long-term effective flood management in Malaysia.
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Ao Li, Dingli Zhang, Zhenyu Sun, Jun Huang and Fei Dong
The microseismic monitoring technique has great advantages on identifying the location, extent and the mechanism of damage process occurring in rock mass. This study aims to…
Abstract
Purpose
The microseismic monitoring technique has great advantages on identifying the location, extent and the mechanism of damage process occurring in rock mass. This study aims to analyze distribution characteristics and the evolution law of excavation damage zone of surrounding rock based on microseismic monitoring data.
Design/methodology/approach
In situ test using microseismic monitoring technique is carried out in the large-span transition tunnel of Badaling Great Wall Station of Beijing-Zhangjiakou high-speed railway. An intelligent microseismic monitoring system is built with symmetry monitoring point layout both on the mountain surface and inside the tunnel to achieve three-dimensional and all-round monitoring results.
Findings
Microseismic events can be divided into high density area, medium density area and low density area according to the density distribution of microseismic events. The positions where the cumulative distribution frequencies of microseismic events are 60 and 80% are identified as the boundaries between high and medium density areas and between medium and low density areas, respectively. The high density area of microseismic events is regarded as the high excavation damage zone of surrounding rock, which is affected by the grade of surrounding rock and the span of tunnel. The prediction formulas for the depth of high excavation damage zone of surrounding rock at different tunnel positions are given considering these two parameters. The scale of the average moment magnitude parameters of microseismic events is adopted to describe the damage degree of surrounding rock. The strong positive correlation and multistage characteristics between the depth of excavation damage zone and deformation of surrounding rock are revealed. Based on the depth of high excavation damage zone of surrounding rock, the prestressed anchor cable (rod) is designed, and the safety of anchor cable (rod) design parameters is verified by the deformation results of surrounding rock.
Originality/value
The research provides a new method to predict the surrounding rock damage zone of large-span tunnel and also provides a reference basis for design parameters of prestressed anchor cable (rod).
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Hau Ching Phyllis Chung and Kemi Adeyeye
The purpose of this paper is twofold: first, to investigate the flood impact on a detached dwelling based on physical attributes related to the positioning, form and orientation…
Abstract
Purpose
The purpose of this paper is twofold: first, to investigate the flood impact on a detached dwelling based on physical attributes related to the positioning, form and orientation of the house, and second, to investigate the effectiveness of property-level protection (PLP) to mitigate the direct structural damage of the house and the degree of floodwater ingress within the house.
Design/methodology/approach
The methods included modelling and simulation within the ANSYS Fluent® computational fluid dynamics software. Flooding scenarios with constrained parameters using theoretical modelling methods/tools were used to test the research hypotheses. Therefore, the results obtained will match the what-if scenarios considered if/based on the standard equations and assumptions made in the idealised model.
Findings
It was found that the position, orientation and form of an individual dwelling with brick and block construction informs the impact of the applied pressure on the structure and water ingress. Increase in pressure on the structure was noted from 0.3 m. All examined PLP mitigated the risk of structural damage if applied in consideration with other interventions e.g. mortar sealing. The use of non-return valves could potentially increase the pressure on the structure, but was also found to be effective in reducing water ingress. Findings should be considered in conjunction with the assumptions and exceptions of this study.
Research limitations/implications
The limitations of this study are that the findings are based on an idealised model of a single detached house, with no landscape obstruction to the watercourse. This mathematical approach concerned with developing the normative models may therefore not fully describe the real-world complex phenomena. But it provides the first vision and an objective basis to answer the questions under study, and to propose usable outputs. Flooding caused from internal sources (e.g. bursting of pipes, roof leaks) or seepage from the ground and moisture through the walls were excluded. Building content was not modelled.
Practical implications
Common property-level flood interventions are typically tested to mitigate water ingress to the house. This study extends this approach to include the prevention of structural damage to the external walls; this can help to avoid the indiscriminate use of property-level flood prevention solutions without full understanding of their degree of effectiveness or impact on the building’s structural integrity. This study is practically significant because it provides outputs and means to examine which intervention(s) are better for delivering flood protection to a standard brick/block detached house type. This knowledge is highly beneficial for relevant stakeholders who can use it to deliver effective property-level flooding resilience measures.
Originality/value
The study provides useful insights for property owners and building professionals to explore suitable, cost-effective single property-level protection against flooding. Furthermore, the effective implementation of interventions can be used to achieve a customised, “fit for purpose” resilience retrofit.
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Rajkishor, Pradeep Bhargava, Navratan M. Bhandari and Umesh K. Sharma
This paper aims to present a mathematical model of predicting the residual moment capacity of fire-damaged reinforced concrete (RC) elements after cooling to ambient temperature…
Abstract
Purpose
This paper aims to present a mathematical model of predicting the residual moment capacity of fire-damaged reinforced concrete (RC) elements after cooling to ambient temperature which also reflects the role of bond between steel rebar and surrounding concrete.
Design/methodology/approach
The prediction of residual moment capacity of fire-damaged RC element has been carried out for two scenarios: by assuming perfect bond between surrounding concrete and steel rebar after fire exposure and by incorporating a relative slip between surrounding concrete and steel rebar and hence assuming partial bond between them after fire scenario. The predicted results are then compared with the experimental results available in different literatures.
Findings
It is found that on comparison between the predicted results and the experimental results, the proposed mathematical prediction model, when bond-characteristics are considered, shows better agreement with the experimental results as compared with those by conventional method with perfect bond assumption.
Originality/value
The constitutive relationship for thermal residual properties of steel rebar and concrete has been used in the proposed prediction model along with relative slip approach between surrounding concrete and steel rebar after fire scenario and consequently to predict the residual moment capacity of the fire-damaged RC element after cooling.
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Bahirathan Koneswaran, Chandana Siriwardana and Ravindu Udayantha Jayasekara
The government-led public healthcare services in Sri Lanka became a major strength in managing the COVID-19 comparatively well. However, natural hazards are a major threat to this…
Abstract
Purpose
The government-led public healthcare services in Sri Lanka became a major strength in managing the COVID-19 comparatively well. However, natural hazards are a major threat to this healthcare system, as they cause severe damages, especially to curative healthcare infrastructures such as hospitals. Floods have been the major contributor to the economic loss of the Sri Lankan healthcare system. Therefore, the purpose of this study is to develop a proper flood risk assessment framework for Sri Lankan hospitals.
Design/methodology/approach
This research study has attempted to develop a flood vulnerability assessment tool for hospitals using the concept of Depth Damage Functions (DDFs). Flood vulnerability curves have been developed for identified critical units of hospitals considering the damage caused to building contents which are predominantly expensive medical equipment. The damage caused only by wetting was considered in generating vulnerability curves. Structured interviews were conducted with government officials in the healthcare sector to gather details on the cost and damages of medical equipment. Pilot studies were carried out in two hospitals identified as located in flood-prone areas and have previous experiences of flooding, to acquire data regarding building contents of the critical units.
Findings
The developed vulnerability curves indicate that no major damage would occur to building contents in critical units (other than the labor room) until the inundation depth reaches a value of 0.6–0.9 m (varies for each type of unit). It is also noteworthy that after a certain range in the inundation depth, the damage increases drastically, and building contents would incur total damage if the inundation depth passes a value of 1.2–1.5 m.
Originality/value
This study explains the initial phase of developing a flood vulnerability assessment framework for Sri Lankan hospitals. Not many studies had been carried out to assess the vulnerability of hospitals specifically for floods using vulnerability curves. The study recommends a zoning system with pre-defined vulnerability levels for critical units during a flood, which can be associated with evacuation planning as well. Further studies must be carried out to verify this system for hospitals in Sri Lanka.
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Robby Soetanto and David G. Proverbs
Flood damage to domestic properties can be considered as a function of two key factors, that is, the flood characteristics and characteristics of the property. A thorough…
Abstract
Flood damage to domestic properties can be considered as a function of two key factors, that is, the flood characteristics and characteristics of the property. A thorough literature review identified that little or no consideration is given to the characteristics of flood when assessing flood‐damaged domestic properties. This paper presents the perceptions of 289 building surveyors regarding flood characteristics as part of a 2‐year research project to benchmark the assessment of flood‐damaged domestic properties in the UK. Surveyors perceived the sewage, fasciae and contaminant content, and depth of the floodwater. Findings also revealed that methods to determine these factors were primarily a function of individual subjective perceptions. Definitive guidance is therefore, needed to minimise variations in subsequent repair and reinstatement works.
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