Toshikazu Hanazato

Seismic and Wind Performance of Five-Storied Pagoda of Timber Heritage Structure

In Japan, there exist a total of 22 five-storied timber pagodas constructed before the middle of 19 centuries. All of those pagodas are registered as the important cultural heritages by Japanese Government, while some of them are listed in World Cultural Heritages such as Horyu-ji Temple’s Pagoda that was built in the end of 7th century. As those timber pagodas in seismic areas have survived against earthquakes during their long histories, their earthquake resistant capacity has been studied for a century. However, the actual dynamic behaviors of timber pagodas subjected to large earthquakes should be recorded to understand the seismic performance. Furthermore, an interesting structural issue has recently risen of wind resistant capacity of traditional five-storied timber pagodas, as such tall timber structures may be severely affected by strong wind. In order to record the actual dynamic behaviors during not only earthquakes but also typhoons, we have been conducting earthquake and wind monitoring at Hokekyou-ji Temple in Ichikawa City, next to Tokyo, which has survived for 4 centuries against not only large earthquakes but also severe typhoons. Hence, while the earthquake monitoring has been done by the conventional method utilizing accelerometers, the dynamic displacement of the structural response to wind has been directly measured by a new technique employing an image process system using LED makers and CCD camera, because the wind response includes much longer period component in general, therefore, it must be difficult to measure accurately the wind response by accelerometers. The scope of the present paper are 1) to review the past studies to understand the excellent earthquake resistance of five-storied timber pagodas, as well as, to introduce our research project of seismic and wind monitoring that has been successfully conducted since 2007, 2) to interpret those monitoring records which would be useful for understanding seismic and wind performance of the heritage timber pagodas that have survived for many centuries with describing the simulation analysis of seismic response, and 3) to show the long term monitoring records of the horizontal displacement of the heritage structure.

Seismic Behaviour of a Historic Five-Tiered Pagoda in Nepal

The present paper discusses a five-tier pagoda in Nepal from the viewpoint of the damage observed after an earthquake. Nepal is a highly seismic-prone country and many structures experience significant damage during earthquakes. Structures are typically composed of timber and masonry which consists of burnt or sundried bricks and mud mortar. The Kathmandu Valley including three major Nepalese cities Bhaktapur, Kathmandu, Patan has been inscribed on the World Heritage List since 1979 as a representative example of unique Newari culture. In the paper, Kumbeshwar temple in Patan is studied. The top-tier was collapsed after the earthquake occurred in Nepal in 2015. The collapse mechanism is described and studied through kinematic limit analysis and preliminary FE analysis. The paper introduces an architecturally characteristic monument in Nepal and would contribute to understanding of seismic behaviour of multi-tier pagodas.

Shaking Table Test of Full Scale Model of Timber Framed Brick Masonry Walls for Structural Restoration of Tomioka Silk Mill, Registered as a Tentative World Cultural Heritage in Japan

Tomioka Silk Mil is the first model silk-reeling factory that the Japanese Government established in 1872. The main building is structurally characterized by timber framed brick masonry walls. The buildings were constructed using European and Japanese traditions. Walls were built of locally produced bricks, manufactured using a technique introduced from Europe, and the buildings were roofed with traditional Kawara tiles. The scope of the paper is to present the outcomes of the shaking table tests using full-scale model of the timber framed brick masonry walls. Those tests were successfully conducted to study the seismic behaviors of such composite structures under extremely strong motions. As well as, they were performed to examine the effectiveness of the proposed strengthening technique using aramid fiber wires. In the present study, 3-dimensional dynamic displacement was directly measured by the image processing technique utilizing high-speed optical cameras. This new technology revealed both the dynamic deformation of the walls and the safety limit of the displacement in dynamic phase.

SEISMIC AND STRONG WIND RESPONSE OBSERVATIONS OF NATIONAL HERITAGE FIVE STORY WOOD PAGODA AND ITS CONSIDERATION

NIED, Senior Researcher Mie University Graduate School of Engineering/Faculty of Engineering, Professor Former Tokyo University of the Arts, Visiting Professor Motion behaviors of the national heritage five story wooden pagoda at Hokekyouji temple are observed from 2007. Continuing part 1,modal and response analyses for the pagoda are conducted. The model is made by using the beam vibration modes. Response analyses are carried out for both 3/11 earthquake and strong wind. As results of linear numerical calculations to strong earthquake motion and strong wind, the damping about 5%-10% would be agreed with observed response data. Modal analysis results showed the possibility of resonance between a pagoda frame and center column. However, in actual pagoda, it would be difficult to expect dynamic damper effects because of irregularities of pagoda structure. 構造系 698号

Architectural Structural Survey of Groups of Traditional Timber Houses in South Nias, Indonesia

In Indonesia, a number of race people have theiroriginal architectural culture of traditional timber houses. Most of them havesurvived against large earthquakes in such seismic areas. As they have beenmaintained by the traditional ways so far, it is worth preserving them from ahistorical point of view. The purpose of the present research is to evaluatethe structural characteristics specific to the traditional wooden houses in SouthNias, located to the west of Sumatra. Furthermore, structural restoration usingthe traditional techniques was discussed to propose appropriate methods for thestructural conservation. The traditional timber houses in South Nias that havesurvived against large earthquakes are characterized by an elevated-floorstructure with large diameter columns and braces under the floor. In thepresent international collaborative study, we performed micro-tremormeasurements to evaluate their fundamental dynamic characteristics. As well as,we conducted architectural structural survey to study the structuralcharacteristics and to detect the material’s deterioration. Furthermore, weconducted monitoring of temperature and humidity in the roof structures to knoweffect of the climate conditions on the wooden materials. Material mechanical testsof timbers which used for structure were also conducted to examine thestrength.

Damage to Masonry Buildings

This chapter describes the earthquake and tsunami damage to partially grouted concrete masonry building, fully grouted concrete masonry buildings, and concrete masonry nonbearing walls provided in reinforced concrete moment resisting framed buildings. These are all used in small housing, commercial and office buildings. Damage caused by the earthquake and tsunami on concrete masonry and stone masonry garden walls are also reported in this chapter.

EXPERIMENTAL STUDY ON CONFINED MASONRY STRUCTURE FOR EARTHQUAKE SAFETY DESIGN-Full scale shaking table test and cyclic loading test-:- Full scale shaking table test and cyclic loading test -

The safety of Non-Engineered Construction is one of most urgent issues, because it is main cause of human casualties. Building Research Institute (BRI) and partner institute both in Japan and abroad have been working on safer housing since 2005. Various research and studies for Non-Engineered construction Activities have been conducted towards achieving safer structures. The confined masonry becomes common structure in earthquake prone area recently. This experimental study on confined masonry was conducted through full scale shaking table test in Japan and Peru. This study aims to better understanding the behavior under earthquake, and research for feasible and affordable seismic construction in earthquake prone area.