The Influence of Dowel-Bearing Strength in Designing Timber Pegged Timber Joints

ABSTRACT

The employment of timber pegs in timber structure joints is a widespread technology in the field of timber frame building in the United States, where the Timber Frame Engineering Council has published a special Standard to supplement the National Design Specification for Wood Construction. The authors have been studying the possibility of supplementing the Eurocode 5 design formulas, thought for timber joints with metal connectors, with specifications needed for a reliable design when employing timber pegs. The field of application envisaged is that of restoring timber structures and results obtained until now are quite encouraging. In this step of the research, more attention has been paid to deformation process: fir and chestnut samples have been tested to determine their dowel-bearing behavior with steel and ash timber peg while double-shear plane joints made of the same wood species, and fastened with steel as well as timber pegs, have been analyzed.     

Flexural Behavior of Typical Chinese Traditional Timber Stitching Beams

In Chinese traditional timber buildings, stitching is very common. When the bearing capacity or the rigidity is inadequate, a timber beam is often strengthened with another beam using the stitching method. The timber stitching beams are mainly of two types—the small-top/big-bottom type and the big-top/small-bottom type. To study the bending behavior of these two types of timber stitching beams, including the failure mode, the flexural capacity, the strain distribution at mid-span section, and the maximum deflection, bending tests are carried out on 14 timber stitching beams with Chinese traditional conformation for seven pine beams and seven fir beams. The results show that the failure modes of the small-top/big-bottom type of stitching beams all show brittle fractures at the bottoms of the bottom beams. The failure modes of the big-top/small-bottom type of stitching beams all show brittle fractures at the bottoms of the top beams. The distribution of section strain along the height of each part of the beam basically obeys plane hypothesis. Based on the theoretical and experimental analysis, the calculation formulas of flexural capacity and maximum deflection of these two types of timber stitching beams made of pine and fir are presented.     

The Karschau Ship, Schleswig-Holstein: Dendrochronological Results and Timber Provenance

The felling of the oak trees used to build the Karschau ship took place in or around the AD 1140s. The tree-ring curves from the oak planks from the Karschau Ship match best with site-means from Odense, a medieval town on the island of Funen, Denmark. New research being carried out by the author is allowing the determination of the provenance of ancient oak to a more local level. Through this dendrochronological research, it is now possible to differentiate between small regions of timber sources for shipbuilding, allowing a more nuanced interpretation.
© 2006 The Author     

南方地区古建筑木结构的整体性残损点指标研究

古建筑木结构的残损点指标是对古建筑木结构进行结构安全评估和加固修缮设计的重要指标,目前主要依据1992年制定的《古建筑木结构维护与加固技术规范》(GB 50165—92)中的规定,为了对该规范中的构架整体性残损点指标进行验证和补充,本研究通过对南方地区传统的穿斗木构体系和抬梁木构体系的典型榫卯节点和构架的试验研究,得出两种木构体系结构的整体性关键残损点指标,并与GB 50165—92规范进行比较分析。结果表明:规范规定的抬梁式木构架和穿斗式木构架的局部倾斜残损点比试验结果小,规范值偏于安全。规范中规定的抬梁式木构架梁柱榫卯连接残损点略小于试验结果,规范值偏于安全;而规范中规定的穿斗式木构架梁柱榫卯连接残损点对于燕尾榫穿斗木构而言是安全的,但对于透榫穿斗木构而言,则是不安全的。     

The Baptistry of Saint John in Florence: The Scientific Dating of the Timber Structure of the Dome

The construction of the Baptistry of Saint John has a debated and uncertain history; the hypothesis on its main construction phases may span from the Roman period to the 13th century, according to different authors. This uncertainty is mainly due to the lack of primary sources and certain dating issues. By combining dendrochronological analysis and radiocarbon dating, some light was shed on the building’s history. Open at least from 897, in 1059 Pope Nicholas II re-consecrated the baptistry after several renovations. Around that period, the octagonal dome was probably built by using chestnut beams to tie the structure together. The dendrochronological analysis dated the silver fir element to 1268. This element possibly represents a replacement coincident with the period, between 1270 and 1300, when a substantial part of the mosaics of the dome was positioned.     

Structural Assessment of Companhia Aurífícia,a 19th Century Industrial Building Located in Northern Portugal

Companhia Aurifícia is located in Porto, Portugal, and was founded in 1864. It was a pioneer factory in the industrial production, casting, rolling, and stamping of metallic objects and laboured for about 150 years, in areas as jewelry, manufacture of parts in silver and gold or the production, and casting of various metals. In 1866, it began laboring in Rua dos Bragas, its present location, and in 2003 ceased all activities.Companhia Aurifícia is an industrial complex including several buildings, all located in the same block. It is a precious example of the industrial architecture in Porto, where the still existent retaining walls, structures, machinery, and decorative elements make it one of the last examples of 19^th century industrial life of the city.This article aims to evaluate the safety condition of one of the buildings included in this industrial complex, in order to propose the necessary strengthening interventions.     

从朝鲜时代的宫中仪礼看遮日的功能和特性——以19世纪以后宫中宴享为中心

朝鲜时代宫中举行仪礼行事时,经常排设和使用一种名为“遮日”的能够隔断日射和降雨的幕构造设施。作者以19世纪以后宫中宴享为中心分析了遮日的功能与特性,详细探讨了遮日的构成、种类、材料和排设方式等具体特性,并对在宫中仪礼行事的举行地如何使用遮日加以推断性的复原。     

英华殿大木结构实测研究

本文在对英华殿大木结构进行详细测量、获取大量较高精度数据的基础上,推算出古代匠人在进行大木尺寸设计中采取以下基本方法:1、本案营造尺长316.5毫米;2、以2尺5寸为基本模数确定柱头平面丈尺;3、采用平面柱头通进深之1/2并结合结构细部设计分别确定檐柱通高、金柱净高;4、以2寸5分为基本模数确定步架;5、采用宋《营造法式》制度确定屋架总举架高,并结合适当的举架比例确定各举高度。     

Rotational behavior of degraded traditional mortise-tenon joints: experimental tests and hysteretic model

This article presents the results of an experimental study on the rotational behavior of degraded Chinese traditional mortise-tenon joints with different degradation types and different degradation degrees. Six joint specimens degraded through artificially simulated method, were tested by reversed cyclic loading, from which the moment-rotation curves were obtained. The results indicated that the rotational behavior of these joints is semi-rigid, the hysteretic curve shapes of degraded joints are same to that of joint without degradation. The maximum moment, yield moment, and initial rotational stiffness of degraded joints decreases as the degraded degree increases, whose empirical degradation relationships were obtained based on the test data. A hysteretic model for degraded traditional mortise tenon joints was proposed. Experimental results were used to validate the proposed hysteretic model. Good agreement between predictions and tests was observed.