ANALYSIS,TESTING AND DESIGN OF STEEL ROOF DECK DIAPHRAGMS FOR DUCTILE EARTHQUAKE RESISTANCE

An experimental program was conducted to study the inelastic response of steel roof deck diaphragms for low-rise steel buildings subjected to seismic loading. Tests were performed on 3.6 m×6.1 m diaphragm specimens made of corrugated steel deck panels. The parameters examined were the thickness and configuration of the sheet steel panels, the type and spacing of the fasteners, the applied loading history and the influence of end lap joints. Diaphragms built with screwed side lap fasteners and nailed deck-to-frame connectors exhibited a pinched hysteretic behaviour, but could sustain large inelastic deformation cycles with limited strength degradation. This type of diaphragm construction could be designed to resist earthquake effects in the inelastic range. Higher shear resistance and less pinching was observed for systems that included welded with washer connections. However, their strength decreased rapidly after the peak load was reached, and hence, these systems should be designed for limited inelastic response. Deck systems with button punched side laps and frame welds without washers showed a brittle response and should be designed to remain elastic under severe earthquake motions. The inelastic demand was found to increase when the spacing of the fasteners was reduced. Specimens constructed with an internal overlap joint exhibited extensive warping of the cross section mainly due to the shorter panel length.     

SEISMIC DESIGN AND ANALYSIS OF A KNEE BRACED FRAME BUILDING

A five-storey steel frame incorporating dissipative knee elements is designed using the Eurocode 8 pushover analysis method. The non-linear analysis makes use of a novel knee element model capable of accurately simulating the bending and shear behaviour observed in full-scale tests. The performance of the structure is assessed using non-linear time-history analysis. This shows that the knee elements can be designed to yield under small earthquakes or early in a strong one (maximising their energy dissipation) while still being able to withstand a large event without collapse. Knee elements thus have the potential to give excellent seismic performance in steel framed structures. The time history analysis results are compared to those obtained with the three different pushover analysis methods (Eurocode 8, FEMA 356 and ATC 40). The FEMA 356 method, which includes a more accurate representation of the structure's significant post-yield stiffness, gave the closest agreement with the time history analyses, while the Eurocode 8 method gave rather conservative results and the ATC 40 method appears non-conservative for this type of structure.     

4. THE GADAMERIAN APPROACH TO THE RELATION BETWEEN EXPERIENCE AND LANGUAGE

Narrativism as a theory of historical depiction intuitively opens the question: what is left of reality when it is poured through the filter of language structures? And, extended a little bit further, questions arise: What is responsible for the final shape of a historical depiction? Is it experience or language? What is affecting what? Narrativism typically accuses language units of transforming experience in a specific way. However, even in asking these questions, the problem of the separation of experience from language and language from experience remains. In this article, I address this issue using Gadamer's hermeneutical frame. Wherever philosophical tradition insists on the separation of certain positions, Gadamer tries to show their ontological connections. For Gadamer, understanding is a basic ontological structure, within which both sides of a dialogue affect and constitute each other. In Gadamerian hermeneutical ontology, there is no “starting point” or first responsible position. In the understanding, dialogue has the permanently moving character of a play, where separate positions are erased. This Gadamerian view can also be applied to the question of language and experience and their mutual connection in depicting any experience via language. In Gadamer's example of the work of art, the original subject matter (Urbild) is articulated through its depiction. The subject matter dictates possible ways of depicting, which in turn dictate the final shape of depiction. In this article, I discuss Gadamer's term “articulation of the world,” by which he means a function of language. Articulation is simply a transformation of shapeless matter into a shape, and in our case it is a transformation of an experience into a language depiction. I show that the Gadamerian approach to language and experience can offer an interesting perspective on the issues discussed in reaction to narrativist philosophy of history.     

Assessing Recovery from the 2004 Indian Ocean Tsunami: An Application of Night‐time Light Data and Vegetation Index

It has been 10 years since the Indian Ocean Tsunami caused serious damage to the coastal areas in South and Southeast Asia. The effects on vegetation and human settlements in the affected areas were enormous. This study presents the results of an analysis estimating the long‐term recovery using two longitudinal remotely sensed dataset: 1. Moderate Resolution Imaging Spectroradiometer enhanced vegetation index (MODIS EVI), a dataset accounting for change in the landscape and vegetation; and 2. Defense Meteorological Satellite Program‐Optical Line Scanner (DMSP‐OLS) night‐time light data in order to estimate the effects on human and economic activities. It is evident from the results of this study that the night‐time light and vegetation index datasets can both be beneficial in identifying changes caused by natural disasters and can be used to track recovery. The results using night‐time light indicates a large loss of lighted area but also a rapid recovery of night‐time light after the tsunami. Already in year 2005–2006, the levels of lighted area and sum of the lighting (SOL) intensity reached the same levels as pre‐tsunami. For MODIS vegetation index, a drop can be observed in 2005/2006 on locations close to the coastline using 1 year temporal resolution; however, when utilizing the 16 day temporal resolution, the impact of the tsunami is illustrated as a dramatic drop, mostly in pixels located within 3km from the coast. Following the drop in vegetation index due to the tsunami, it was observed that most pixels exhibited at least some level of recovery in 2 years after the event.