An Overview of Non – Engineered Buildings Roofing System Failure under Wind Loads

2015 ◽  
Vol 802 ◽  
pp. 89-94 ◽  
Author(s):  
Mohd Khairul Azuan Muhammad ◽  
T.A. Majid ◽  
Noram I. Ramli ◽  
S.N.C. Deraman ◽  
Farah Alwani Wan Chik
Keyword(s):  
Monsoon Season ◽  
Geographical Location ◽  
Great Majority ◽  
Peninsular Malaysia ◽  
System Failure ◽  
Northeast Monsoon ◽  
Strong Wind ◽  
Engineered Structures ◽  
Wind Events ◽  
Roofing System

Strong wind is an annual natural hazard in Malaysia due to the geographical location. The northeast monsoon season usually commences in early November and ends in March. During this season, steady easterly or northeasterly winds of 10 to 20 knots prevail. The strong wind events such as hurricane and storms often caused severe damage to the large number of low rise building especially at the roofing system. At end of year 2014, the series of thunderstorm hit the Northern area of Peninsular Malaysia and caused million ringgit losses. This paper is focused on the roofing system failure of the low rise houses at the rural area that constitute the great majority of the infrastructure in less affluent communities. These non-engineered structures are typically built with very little, or no technical engineering input, and are often the product of varied building traditions and cultures.

scholarly journals Statistical Modeling of RPCA-FCM in Spatiotemporal Rainfall Patterns Recognition

Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 145
Author(s):  
Siti Mariana Che Mat Nor ◽  
Shazlyn Milleana Shaharudin ◽  
Shuhaida Ismail ◽  
Sumayyah Aimi Mohd Najib ◽  
Mou Leong Tan ◽  
...  
Keyword(s):  
Statistical Modeling ◽  
East Coast ◽  
Monsoon Season ◽  
Clustering Algorithms ◽  
Breakdown Point ◽  
Peninsular Malaysia ◽  
Northeast Monsoon ◽  
Number Of Components ◽  
Torrential Rainfall ◽  
Rainfall Patterns

This study was conducted to identify the spatiotemporal torrential rainfall patterns of the East Coast of Peninsular Malaysia, as it is the region most affected by the torrential rainfall of the Northeast Monsoon season. Dimension reduction, such as the classical Principal Components Analysis (PCA) coupled with the clustering approach, is often applied to reduce the dimension of the data while simultaneously performing cluster partitions. However, the classical PCA is highly insensitive to outliers, as it assigns equal weights to each set of observations. Hence, applying the classical PCA could affect the cluster partitions of the rainfall patterns. Furthermore, traditional clustering algorithms only allow each element to exclusively belong to one cluster, thus observations within overlapping clusters of the torrential rainfall datasets might not be captured effectively. In this study, a statistical model of torrential rainfall pattern recognition was proposed to alleviate these issues. Here, a Robust PCA (RPCA) based on Tukey’s biweight correlation was introduced and the optimum breakdown point to extract the number of components was identified. A breakdown point of 0.4 at 85% cumulative variance percentage efficiently extracted the number of components to avoid low-frequency variations or insignificant clusters on a spatial scale. Based on the extracted components, the rainfall patterns were further characterized based on cluster solutions attained using Fuzzy C-means clustering (FCM) to allow data elements to belong to more than one cluster, as the rainfall data structure permits this. Lastly, data generated using a Monte Carlo simulation were used to evaluate the performance of the proposed statistical modeling. It was found that the proposed RPCA-FCM performed better using RPCA-FCM compared to the classical PCA coupled with FCM in identifying the torrential rainfall patterns of Peninsular Malaysia’s East Coast.

scholarly journals Flood and Flash Flood Geo-Hazards in Malaysia

2018 ◽  
Vol 7 (4.35) ◽  
pp. 760
Author(s):  
F. S. Buslima ◽  
R. C. Omar ◽  
Tajul Anuar Jamaluddin ◽  
Hairin Taha
Keyword(s):  
East Coast ◽  
Flash Flood ◽  
Monsoon Season ◽  
Rapid Development ◽  
Flash Floods ◽  
Peninsular Malaysia ◽  
Northeast Monsoon ◽  
Natural Phenomena ◽  
Subject Matter Experts ◽  
Rapid Rise

Floods are natural phenomena of geo-hazards that usually happened when experiencing prolonged heavy rainfalls. Floods in Malaysia can be categorized into monsoon floods and flash floods. Monsoon floods is caused of Northeast Monsoon season commences in early November and ends in March that brings heavy rainfall, particularly to the east coast states of Peninsular Malaysia and western Sarawak. Flash floods usually occur in areas with rapid development by a rapid rise in water level, high velocity, and large amounts of debris. Flooding that occurred in December 2014 can be classified as worst floods that affected several states in Peninsular Malaysia, and the worst affected is Kelantan state. This disaster was recorded more than 200,000 people were affected with 21 people were killed and gives a massive impact on people, properties, agriculture, livestock, and infrastructure facilities. Following the worst floods that hit Malaysia in 2014, the opinions and views from various parties such as subject matter experts was needed to produce mitigations and prevents of the flood disaster at once to minimize vulnerability to hazard.

scholarly journals Heavy rain and strong wind events and cyclones in the Balearics

2006 ◽  
Vol 7 ◽  
pp. 73-77 ◽  
Author(s):  
J. Campins ◽  
A. Jansà ◽  
A. Genovés
Keyword(s):  
Three Dimensional ◽  
Geographical Location ◽  
Heavy Rain ◽  
Balearic Islands ◽  
Dimensional Structure ◽  
Strong Wind ◽  
Affected Area ◽  
Three Dimensional Structure ◽  
Wind Events ◽  
The Relationship

Abstract. The relationship between heavy rain (HR) and/or strong wind (SW) events and cyclones is investigated for the Balearic Islands. First, a list of HR and SW events is cross-referenced with an objective cyclone database for a 9-year period (from June 1995 to May 2004). The presence of a cyclone centre close to the Balearics is looked for each event. For HR events in most of the cases a cyclone centre is located in the vicinity. Furthermore, cyclones are located in such a way that allow the supply of warm and wet air to the affected area. But for SW events, although in the majority of cases a cyclone centre is detected, cyclones are located farther than for HR events and their geographical location is more widespread. Afterwards, the three-dimensional structure of cyclones related to HR and/or SW events is studied in detail.

Non-Homogeneous Hidden Markov Model for Daily Rainfall Amount in Peninsular Malaysia

2013 ◽  
Vol 63 (2) ◽  
Author(s):  
Wei Lun Tan ◽  
Fadhilah Yusof ◽  
Zulkifli Yusop
Keyword(s):  
Markov Model ◽  
Hidden Markov Model ◽  
Large Scale ◽  
Hidden Markov ◽  
Monsoon Season ◽  
Daily Rainfall ◽  
Reanalysis Data ◽  
Peninsular Malaysia ◽  
Northeast Monsoon ◽  
Hidden States

The non-homogeneous hidden Markov model (NHMM) generates the rainfall observation depends on few weather states which serve as a link between the large scale atmospheric measures. The daily rainfall at 20 stations from Peninsular Malaysia for 33 years sequences is analyzed using NHMM during the northeast monsoon season. A NHMM with six hidden states are identified. The atmospheric variable was obtained from NCEP Reanalysis Data as predictor. The gridded atmospheric fields are summarized through the principle component analysis (PCA) technique. PCA is applied to sea level pressure (SLP) to identify their principal spatial patterns co-varying with rainfall. The NHMM can accurately simulate the observed daily mean rainfall, correlations between stations for daily rainfall amounts and the quantile-quantile plots. It can be concluded that the NHMM is a useful method to simulate the daily rainfall amounts that may be used to prepare strategies and planning for the unpredicted disaster such as flood and drought.

scholarly journals The intensity of slope and fluvial processes after a catastrophic windthrow event in small catchments in the Tatra Mountains

2021 ◽  
Vol 18 (6) ◽  
pp. 1405-1423
Author(s):  
Dariusz Strzyżowski ◽  
Elżbieta Gorczyca ◽  
Kazimierz Krzemień ◽  
Mirosław Żelazny
Keyword(s):  
Environmental Changes ◽  
Bedload Transport ◽  
Strong Wind ◽  
Tatra Mountains ◽  
Salvage Logging ◽  
Fluvial Processes ◽  
Wind Events ◽  
And Control ◽  
The Tatra Mountains ◽  
The Impact

AbstractStrong wind events frequently result in creating large areas of windthrow, which causes abrupt environmental changes. Bare soil surfaces within pits and root plates potentially expose soil to erosion. Absence of forest may alter the dynamics of water circulation. In this study we attempt to answer the question of whether extensive windthrows influence the magnitude of geomorphic processes in 6 small second- to third-order catchments with area ranging from 0.09 km2 to 0.8 km2. Three of the catchments were significantly affected by a windthrow which occurred in December 2013 in the Polish part of the Tatra Mountains, and the other three catchments were mostly forested and served as control catchments. We mapped the pits created by the windthrow and the linear scars created by salvage logging operations in search of any signs of erosion within them. We also mapped all post-windthrow landslides created in the windthrow-affected catchments. The impact of the windthrow on the fluvial system was investigated by measuring a set of channel characteristics and determining bedload transport intensity using painted tracers in all the windthrow-affected and control catchments. Both pits and linear scars created by harvesting tend to become overgrown by vegetation in the first several years after the windthrow. The only signs of erosion were observed in 10% of the pits located on convergent slopes. During the period from the windthrow event in 2013 until 2019, 5 very small (total area <100 m2) shallow landslides were created. The mean distance of bedload transport was similar (t-test, p=0.05) in most of the windthrow-affected and control catchments. The mapping of channels revealed many cases of root plates fallen into a channel and pits created near a channel. A significant amount of woody debris delivered into the channels influenced the activity of fluvial processes by creating alternating zones of erosion and accumulation.

scholarly journals A methodology to conduct wind damage field surveys for high-impact weather events of convective origin

2020 ◽  
Vol 20 (5) ◽  
pp. 1513-1531 ◽  
Author(s):  
Oriol Rodríguez ◽  
Joan Bech ◽  
Juan de Dios Soriano ◽  
Delia Gutiérrez ◽  
Salvador Castán
Keyword(s):  
Field Studies ◽  
High Impact ◽  
Strong Wind ◽  
Field Surveys ◽  
Weather Events ◽  
Straight Line ◽  
High Impact Weather ◽  
Strong Winds ◽  
Wind Events ◽  
The One

Abstract. Post-event damage assessments are of paramount importance to document the effects of high-impact weather-related events such as floods or strong wind events. Moreover, evaluating the damage and characterizing its extent and intensity can be essential for further analysis such as completing a diagnostic meteorological case study. This paper presents a methodology to perform field surveys of damage caused by strong winds of convective origin (i.e. tornado, downburst and straight-line winds). It is based on previous studies and also on 136 field studies performed by the authors in Spain between 2004 and 2018. The methodology includes the collection of pictures and records of damage to human-made structures and on vegetation during the in situ visit to the affected area, as well as of available automatic weather station data, witness reports and images of the phenomenon, such as funnel cloud pictures, taken by casual observers. To synthesize the gathered data, three final deliverables are proposed: (i) a standardized text report of the analysed event, (ii) a table consisting of detailed geolocated information about each damage point and other relevant data and (iii) a map or a KML (Keyhole Markup Language) file containing the previous information ready for graphical display and further analysis. This methodology has been applied by the authors in the past, sometimes only a few hours after the event occurrence and, on many occasions, when the type of convective phenomenon was uncertain. In those uncertain cases, the information resulting from this methodology contributed effectively to discern the phenomenon type thanks to the damage pattern analysis, particularly if no witness reports were available. The application of methodologies such as the one presented here is necessary in order to build homogeneous and robust databases of severe weather cases and high-impact weather events.

Lessons learnt at the Met Office from the Great Storm of 1987 - a comparison with recent strong wind events

Weather ◽  
2012 ◽  
Vol 67 (10) ◽  
pp. 268-273 ◽  
Author(s):  
Alexander Fox ◽  
Rebekah Sherwin ◽  
Fraser Ralston
Keyword(s):  
Strong Wind ◽  
Lessons Learnt ◽  
Wind Events

scholarly journals Design of a scanning laser meter for monitoring the spatio-temporal evolution of snow depth and its application in the Alps and in Antarctica

2016 ◽  
Vol 10 (4) ◽  
pp. 1495-1511 ◽  
Author(s):  
Ghislain Picard ◽  
Laurent Arnaud ◽  
Jean-Michel Panel ◽  
Samuel Morin
Keyword(s):  
Spatial Variability ◽  
Snow Depth ◽  
Laser Scanning ◽  
Single Point ◽  
Measurement Techniques ◽  
Strong Wind ◽  
Slow Increase ◽  
Automatic Instrument ◽  
Spatio Temporal ◽  
Wind Events

Abstract. Although both the temporal and spatial variations of the snow depth are usually of interest for numerous applications, available measurement techniques are either space-oriented (e.g. terrestrial laser scans) or time-oriented (e.g. ultrasonic ranging probe). Because of snow heterogeneity, measuring depth in a single point is insufficient to provide accurate and representative estimates. We present a cost-effective automatic instrument to acquire spatio-temporal variations of snow depth. The device comprises a laser meter mounted on a 2-axis stage and can scan  ≈  200 000 points over an area of 100–200 m2 in 4 h. Two instruments, installed in Antarctica (Dome C) and the French Alps (Col de Porte), have been operating continuously and unattended over 2015 with a success rate of 65 and 90 % respectively. The precision of single point measurements and long-term stability were evaluated to be about 1 cm and the accuracy to be 5 cm or better. The spatial variability in the scanned area reached 7–10 cm (root mean square) at both sites, which means that the number of measurements is sufficient to average out the spatial variability and yield precise mean snow depth. With such high precision, it was possible for the first time at Dome C to (1) observe a 3-month period of regular and slow increase of snow depth without apparent link to snowfalls and (2) highlight that most of the annual accumulation stems from a single event although several snowfall and strong wind events were predicted by the ERA-Interim reanalysis. Finally the paper discusses the benefit of laser scanning compared to multiplying single-point sensors in the context of monitoring snow depth.

scholarly journals SPATIO-TEMPORAL ESTIMATION OF INTEGRATED WATER VAPOUR OVER THE MALAYSIAN PENINSULA DURING MONSOON SEASON

2017 ◽  
Vol XLII-4/W5 ◽  
pp. 165-175
Author(s):  
S. Salihin ◽  
T. A. Musa ◽  
Z. Mohd Radzi
Keyword(s):  
Water Vapour ◽  
Monsoon Season ◽  
Temporal Distribution ◽  
Southwest Monsoon ◽  
Northeast Monsoon ◽  
Path Delay ◽  
Zenith Path Delay ◽  
Temporal Estimation ◽  
Integrated Water Vapour ◽  
Spatio Temporal

This paper provides the precise information on spatial-temporal distribution of water vapour that was retrieved from Zenith Path Delay (ZPD) which was estimated by Global Positioning System (GPS) processing over the Malaysian Peninsular. A time series analysis of these ZPD and Integrated Water Vapor (IWV) values was done to capture the characteristic on their seasonal variation during monsoon seasons. This study was found that the pattern and distribution of atmospheric water vapour over Malaysian Peninsular in whole four years periods were influenced by two inter-monsoon and two monsoon seasons which are First Inter-monsoon, Second Inter-monsoon, Southwest monsoon and Northeast monsoon.

scholarly journals Dissolved iron (II) in the Baltic Sea surface water and implications for cyanobacterial bloom development

2009 ◽  
Vol 6 (2) ◽  
pp. 3803-3850 ◽  
Author(s):  
E. Breitbarth ◽  
J. Gelting ◽  
J. Walve ◽  
L. J. Hoffmann ◽  
D. R. Turner ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Surface Waters ◽  
Cyanobacterial Bloom ◽  
Euphotic Zone ◽  
Strong Wind ◽  
Ferrous Ions ◽  
The Baltic Sea ◽  
High Concentrations ◽  
Wind Events ◽  
The Baltic

Abstract. Iron chemistry measurements were conducted during summer 2007 at two distinct locations in the Baltic Sea (Gotland Deep and Landsort Deep) to evaluate the role of iron for cyanobacterial bloom development in these estuarine waters. Depth profiles of Fe(II) were measured by chemiluminescent flow injection analysis (CL-FIA) and reveal several origins of Fe(II) to the water column. Photoreduction of Fe(III)-complexes and deposition by rain are main sources of Fe(II) (up to 0.9 nmol L−1) in light penetrated surface waters. Indication for organic Fe(II) complexation resulting in prolonged residence times in oxygenated water was observed. Surface dwelling heterocystous cyanobacteria where mainly responsible for Fe(II) consumption in comparison to other phytoplankton. The significant Fe(II) concentrations in surface waters apparently play a major role in cyanobacterial bloom development in the Baltic Sea and are a major contributor to the Fe requirements of diazotrophs. Second, Fe(II) concentrations up to 1.44 nmol L−1 were observed at water depths below the euphotic zone, but above the oxic anoxic interface. Finally, all Fe(III) is reduced to Fe(II) in anoxic deep water. However, only a fraction thereof is present as ferrous ions (up to 28 nmol L−1) and was detected by the CL-FIA method applied. Despite their high concentrations, it is unlikely that ferrous ions originating from sub-oxic waters could be a temporary source of bioavailable iron to the euphotic zone since mixed layer depths after strong wind events are not deep enough in summer time.

Sign in / Sign up

Export Citation Format

Share Document