Impact of Moisture Decay on Seismic Vulnerability: Haiti’s Wood-FramedVernacular Buildings

A major and shallow earthquake with a moment magnitude of 7.2 hit Tiburon Peninsula on 14 August 2021, damaging over 137,000 buildings. A hybrid reconnaissance activity was conducted in the aftermath, jointly by EEFIT/StEER/GHI, to evaluate the impact of the event on buildings, infrastructure and communities. The study also included an investigation of the performance of local vernacular homes -wooden frames with infill, which were found to be one of the most vulnerable typologies. Moisture was identified as an agent of damage for 14% of the damage-assessed vernacular housing. This paper examines semi-quantitatively how moisture decay increases the seismic vulnerability of this typology of Haiti

Technological characteristics of abrick masonry structure and their relationship with the structural behaviour /

The aim of this study is to investigate the physical and mechanical properties of construction materials in relation with the structural behaviour of a historic structure. Within this framework, the brick masonry superstructure of Tahir ile Zuhre Mescidi, a XIIIth century Seljuk monument in Konya was selected as case study. The study started with the determination of the basic physical (bulk density, effective porosity, water absorption capacity), mechanical (modulus of elasticity, uniaxial compressive strength), durability and pozzolanic properties of original brick and mortar by laboratory analysis. The obtained data was utilized as material information at the modelling of superstructure, by means of structural analysis software, SAP2000. At the modelling stage, finite element method was used and the complexity of masonry in terms of nonlinearity and heterogeneity was taken into account within practical limits. The constructed model was investigated under dead load, wind load, snow load, temperature load and earthquake load and their possible combinations. Structural investigation was continued with two scenarios representing possible wrong interventions i.e. completion of the partially collapsed superstructure with concrete and the concrete coating over superstructure. These cases were investigated under uniform and randomly distributed temperature loads. The results approved the safety of the superstructure under normal service conditions, defined as the appropriate combinations of dead load, snow load, wind load and temperature load. The structure appeared to be safe under the earthquake load too. The analyses carried out to simulate the inappropriate restoration works demonstrated the structural damage formations at the original structure.M.S. - Master of Scienc

Seismic resistance of traditional timber-frame hımış structures in Turkey: a brief overview

Himis structures have hardly ever found as extensive a role as other traditional timber housing, such as those originating from Japan or Central Europe, within the wide discourse on the seismic performance of timber-frame architecture that has gained significant momentum in the last few decades owing to advancing testing technologies. While the himis construction technique was perhaps not born as a result of a conscious search for a seismically resistant building form, it was soon widely appreciated for its structural features advantageous under seismic loading especially from the sixteenth century when it has become a well-established construction technique in part of the Balkans and in today's Turkey. Despite widely available anecdotal information based on post-disaster studies regarding its performance under earthquakes, robust quantitative data on the seismic behaviour of these structures were practically non-existent until quite recently, and are still somewhat limited. However, we are now able to confirm that himis constructions do have intrinsic qualities that are very beneficial under seismic action. This paper aims to make a brief review of the current state of our knowledge on structural performance of himis buildings under earthquake loading, with specific emphasis on infill/cladding techniques, connection details and energy dissipation characteristics.Publisher's Versio

Önleyici yapısal sağlık izleme metodları, araç ve stratejilerinin araştırılması, geliştirilmesi ve uygulanması

TÜBİTAK MAG01.10.201

Seismic performance evaluation of traditional timber Hımış frames: capacity spectrum method based assessment

Timber constructions have been widely suggested to be seismically resistant based on post-disaster reconnaissance studies. This observation has, however, remained to a large extent anecdotal due to the lack of experimental work supporting it, especially for certain timber architectural forms, including traditional timber frame “hımış” structures. To fill this gap, the authors carried out an extensive full-scale testing scheme using frames of various geometrical configurations, tested under reverse-cyclic lateral loading with/without infill (brick and adobe) or cladding (bağdadi and şamdolma) (Aktas et al. in Earthq Spectra 30(4):1711–1732, 2014a, b). The tests concluded that hımış frames had high energy dissipation capabilities due mostly to nailed connections. Infill/cladding significantly helped improve stiffness and lateral load strength of the frames, and timber type did not seem to make a remarkable impact on the overall behaviour. The current paper, on the other hand, uses test data to calculate capacity/demand ratios based on capacity spectrum method and Eurocode 8 to elaborate more on the performance of “hımış” structures under seismic loading. The obtained results are discussed to draw important conclusions with regards to how frame geometry and infill/cladding techniques affect the overall performance

A multidisciplinary approach to address climate-resilience, conservation and comfort in traditional architecture: The PROT3CT example

Traditional dwellings despite their environmental credentials, due to age, previous damage, and residents unable to afford even the limited maintenance allowed by restrictive legal framework, may offer poor thermal performance, which is expected to be further exacerbated by changing climate. More than 70% of Turkey’s built heritage stock is composed of traditional dwellings, which makes this stock able to create a major impact nationally on the building-related energy use, carbon emissions and population wellbeing. This research aims to develop an evidence-based multidisciplinary methodology for cost-effective retrofit of the traditional dwellings in Turkey, to improve energy performance, satisfy user expectations of comfort, and protect heritage value

Geleneksel Osmanlı ahşap çerçeveli konutlarının deprem dayanımlarının değerlendirilmesi.

The aim of this study is to evaluate the seismic resistance of traditional Ottoman timber frame “hımış” structures, which form the major part of Turkey’s cultural heritage, from an engineering point of view. On the other hand, the seismic resistance of traditional Ottoman timber frame structures was not evaluated from an engineering perspective. For the aim of seismic resistance evaluation of traditional Ottoman timber frame houses, the TUBITAK (the Scientific and Technological Research Council of Turkey) project numbered 106M499 was carried out. Within this framework, 16 tests were carried out in the Structural Mechanics Laboratory of Middle East Technical University, by means of 8 1-1 scale timber frames of different geometrical configurations and material, carefully selected from traditional houses in Safranbolu, representing Ottoman timber frame “hımış” technique. The frames were tested without and with different infill/covering types, and parameters that directly or indirectly indicate the behavior of a structure under earthquake loading were derived from the results obtained at the end of experimental work. In addition, capacity calculations were carried out for each test, using ATC-40 procedure. The results demonstrated that Ottoman timber frame “hımış” houses are seismically resistant, and yet there are a number of important points that should be obeyed in their construction regarding size of diagonal elements, size and placement of openings, intervals between vertical studs, as well as connection details. It is also seen that certain infill/covering materials/methods are more advantageous than the others; for example, covering techniques results in a higher amount of maximum lateral load that the frame can bear under the same displacement. Infill with masonry blocks results in a larger increase in weight than in load bearing capacity. The conclusions drawn are intended to be used not only in the conservation of such structures but they are also expected to direct modern seismically resistant constructions.Ph.D. - Doctoral Progra

REVERSE-ENGINEERING EVALUATION AND MONITORING OF NEMRUT MONUMENTS

The focus of this study is on the Nemrut Dag monuments, which were constructed approximately 2000 years ago at the peak of Mount Nemrut, 2206 meters elevation, are among the most valuable historical heritage sites in Turkey. Since the discovery of Nemrut monuments in 1881, many questions are unresolved, such as how the monuments were destroyed and why the damage level is very different between the symmetric east and west terraces. Natural causes, such as earthquakes, snow, or wind or manmade damages in the case of grave theft attempts with explosives or digging might have caused the damage. This study presents reversed engineering (forensic) approaches for the evaluation of different damage scenarios. The region being approximately 5 km away from East Anatolian Fault zone, the possibility of damaging earthquake occurrence in the past two millennia is quite high. Snow-load evaluations were carried out using the Swiss Guidelines for the Design of Snow Supporting Structures. The nonlinear blast-loading calculations were carried out using LS-DYNA software for the documented crater sizes located on the tumulus. Wind loading was investigated using on-site 4-year monitoring and statistical analysis. Conclusions include the results regarding the failure modes of the monuments and anastylosis/strengthening methods were discussed

Tarihi geleneksel ahşap karkas / hımış konutların sismik performansının değerlendirilmesi

TÜBİTAK MAG01.12.201

Testing and Seismic Capacity Evaluation of a Typical Traditional Ottoman Timber Frame

In Turkey, as well as in Balkan countries, examples of an extant housing tradition namely himis, which was formed during Ottoman period, can still be observed. In spite of minor local differences according to geographical locations, these Ottoman himis houses are distinguished with a number of common architectural and technical peculiarities that is worth to preserve. They have similar timber frame construction system with different infill materials. There are numerous reports claiming that the himis houses are seismically more resistant than other construction types such as reinforced concrete and/or masonry structures. However, nearly all such reports are based on observations made after historical or contemporary earthquakes and lack quantitative engineering approach. For these reasons, within the framework of an ongoing research project, supported by The Scientific and Technological Research Council of Turkey (TUBITAK), coded 106M499, the seismic resistance of traditional timber frame houses in Turkey was investigated. A number of timber frames were tested in the laboratory under cyclic and reverse lateral loading, with and without infill. The results were reproduced with pertinent analytical work. As a result, it was shown that connections that were traditionally made with the sole use of standard nails were always the location of failure. In this paper, the results obtained for one of these frames is presented together with its capacity curve analysis to see whether strengthening is needed or not from seismic design point of view