Mitsuhiro Miyamoto

Assessment of out-of-plane behavior of rammed earth walls by pull-down tests

ABSTRACT This article reports pull-down tests performed on rammed earth construction in Bhutan. The pull–down specimens involved an old rammed earth building component as well as a newly prepared rammed earth wall. Both the wall specimens were tested in out-of-plane direction. Theoretical rigid body formulation and finite element (FE) models were developed to predict the response of the rammed earth structures under out-of-plane loading. The validated FE model was further extended to parametric study of material and physical characteristics of rammed earth construction and their effect on critical response quantities. The change in elastic modulus showed effect in the pre-cracking phase of the wall. Density of rammed earth on the other hand affected the post-peak response of the rammed earth wall. Furthermore, an increase in the physical characteristics, namely, the thickness of wall and the vertical superimposed load on top of the wall, enhanced the rocking resistance capacity of the out-of-plane loaded rammed earth walls.

Full–Scale Pull–Down Tests on a Two–Storied Rammed Earth Building with Possible Strengthening Interventions

This paper reports pull–down tests performed on full–scale two–storied rammed earth (RE) buildings to assess the out–of–plane performance of RE construction in Bhutan. An innovative strengthening technique is also proposed for strength enhancement of the RE walls. The tests involved two types of specimens, an unreinforced RE structure and an identical reinforced counterpart. The pull–down load was applied on top of the facade. The strengthening strategy involved reinforced concrete sections of dowels and wedges inserted between the RE blocks at regular intervals. The wooden floor beams at the first–floor level were also anchored to the RE blocks in the reinforced specimen. Micro–tremor measurements of the structures were done prior to the pull–down tests. A maximum of 59% increment in peak pull–down load was observed for the reinforced RE specimen compared to its unreinforced counterpart. The unreinforced RE wall showed damage to a larger area of facade, whereas, the reinforced RE specimen showed damage to a relatively smaller zone with controlled failure mechanism.

THE REMODELING HISTORY OF THE INOKUMA HOUSE, CULTURAL PROPERTY DESIGNATED BY KAGAWA PREFECTURE

This study aims to trace the remodeling history of the Inokuma house, cultural property designated by Kagawa Prefecture. The Inokuma house has been considered a crucial remains that was built in 1664 and maintain the plan and design at the times. We searched for the remodeling evidences and historical papers indicating the remodeling history. The site plan that was drawn in the Meiwa Period (1764-1771) made it possible to restore the house to its original plan at the time, and 2 old drawings about the massive remodeling in the Meiji Period (18681912) were found.

EXPERIMENTAL STUDY ON SEISMIC PERFORMANCE OF MUD WALL MIXED WITH BAMBOO FIBER

The purpose of this paper is to propose the method of a wall clay mixed with bamboo fiber and to examine experimentally an application for mud walls. First, element tests are performed to grasp a relationship between a length of fiber and mechanical characteristics of wall clay. Second, full-scale static lateral loading tests are performed to examine the strength and the fracture mode of mud walls mixed with bamboo fiber.