Reliability assessment of wooden supported roofs of selected historical churches in Laguna

• Main Authors: Alberto, Bea S., Apacible, Patrick Anthony M., Pacayra, April Oilec Deanielle B., See, Brent J.
• Format: text
• Language: English
• Published: Animo Repository 2017
• Subjects: Structural engineering; Catholic church buildings > Reconstruction; Buildings > Retrofitting
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/9080
• Institution: De La Salle University

The Philippines holds a number of historical structures, proof to the country's vast and rich culture and history. Having intrinsic value, these historical structures serve the country as great tourists attractions and shares in the country's distinct identity. However, due to the geographic location of the Philippines, these historical structures face the risk of damage from natural disasters such as earthquakes and typhoon. In this regard, there is undeniable need to assess historical structures against these natural events. This paper aims to assess the integrity of the wood supported roof structure of four historical churches situated in the province of Laguna located in the Calabarzon region of Luzon against wind loads in extreme scenarios as experienced with the visit of numerous typhoons. Through the use of programs and simulations such as the MCS method in MATLAB and the modelling in SAP2000, along with the equations of the NDSWC and NSCP, the wind data from PAGASA and the on-site survey, the analysis was conducted. It was observed that among the modes of failures that were considered (pull-out, pull-over, compression, tension, and uplift of support failure), the pull-out, pull-over, compression stood out in performance, because these modes performed below the standards of reliability for all four churches set at a value of 3.5. Values for pull-out failure under GEV-simulated loads are 2.97, 3.44, 3.49, and 3.05 for Magadalena (MAG), Majayjay, (MJJ), Paeta (PTE), and Pakil (PKL), respectively. Pull-out values under 300RP wind loads were found to be at 2.6 (MAG), 2.54 (MJJ), 2.28 (PTE), and 2.01 (PKL). The value for pull-over failure under GEV-simulated loads generated 2.65 (MAG), 2.82 (MJJ), 2.80 (PTE), and 2.45 (PKL), while 300RP loads generated 2.51 (MAG), 2.63 (MJJ), 2.61 (PTE), and 2.45 (PKL). The only uplift failure to have been found was for Magdalena wherein both outer supports are expected to have a 2.5 reliability value for the transverse GEV load and a definite failure for the transverse 300RP loads. Overall, the assessment concludes that the reliability of the structure in terms of its modes are greatly affected by the 300-year RP (return period) wind speed, and as such must be considered in the future for restoration and retrofitting of the church structures.