Takumi Aramaki

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.

QUESTIONNAIRE SURVEY FOR COMPONENT MATERIALS AND ERECTION OF CONVENTIONAL FORMWORK BY FORMWORK CONTRACTORS

荒巻卓見ー ーーーー * 1 中田善久ー ーーーー* 2 大塚秀三ー ーーーー * 3 宮田敦典ー ーーーー* 4 キーワード: アンケート調査,型枠工事業者,在来型枠工法,内端太, セパレータ

QUESTIONNAIRE SURVEY TARGETED TO SUBCONTRACTORS ON THE ACTUAL STATE OF DEMOLITION WORK

Until now, demolition work has been upgraded about technical matters and qualification system. However, actual state of demolition work from Engineer and skilled worker’s standpoint has not been fully elucidated. Therefore, the purpose of this study is to investigate the actual state of demolition work by the questionnaire survey targeted to subcontractors. As a result, this paper showed the actual state of demolition work about preliminary survey, calculation, consciousness of accepting order and contract system, construction scheme, construction control and human materials.

IMPROVEMENT IN CONCRETE SURFACE PROTECTION ABILITY USING BOTH SILANE AND SILANE-SILOXANE LAYERS

In order to improve in concrete surface protection ability with retaining its low gloss, two types of silane penetrant (silane-1 and silane-2), one type of silane-siloxane surface coating material and the standard commercial penetrant were examined. The silane penetrants having different reaction speeds were individually coated on the concrete surface. The silane-1 deeply penetrated than the silane-2. However, the silane-2 which reacts faster than the silane-1 showed the excellent properties of preventing water permeability, carbonation and chloride-ion penetration. This is supposed that it generated steadier and thicker siloxane-bond network in the inner side of the pores of the treated concrete than the other. Treatment with both silane and silane-siloxane layers showed much better properties than a single treatment of them. The combination of the silane-2 and silane-siloxane layers gave the best durability to the concrete surface among the surface treatment materials. The gloss measurement showed that the specimens coated with the silanes had low glosses as same as the untreated one. On the other hand, the specimens with the silane-siloxane resulted having high glosses because of its own high gloss.