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.     

CHANGES IN THE METAL CONTENT OF HUMAN HAIR DURING DIAGENESIS FROM 500 YEARS,EXPOSURE TO GLACIAL AND AQUEOUS ENVIRONMENTS

Scanning electron microscopy, inductively coupled plasma mass spectroscopy and time‐of‐flight secondary ion mass spectrometry have been used to examine the extent and possible mechanisms by which the metal content of human hair is altered by exposure to aqueous environments. The results, using both modern hair and samples from 500‐year‐old hair associated with glacier‐entombed remains, show that the metal content has been altered sufficiently so that the interpretation of the metal signature in terms of diet or disease is problematic. While endogenous information is difficult to glean from these data, interesting observations have been made of possible early stages of mineral authigenic deposition. The chemistry of the outer hair surface was found to be consistent with deposition of Fe and Al silicates, as well as other mineral phases. The ancient hair was analysed at the root region and included a comparison of the internal versus external composition to assist in identifying the diagenetic processes.     

London-Bahrain Archaeological Expedition excavations at Saar: 1993 season

During 1993, the London-Bahrain Archaeological Expedition conducted a fourth season of excavations at the early second millennium settlement of Saar, Bahrain. A lower level of the temple was cleared, and a range of buildings to its north-west discovered. A new street was found opposite the temple entrance, and several of the buildings along the main street were further investigated. Further environmental research included a new programme of micromorphology and the start of research into the fish remains.     

POTS AND PITS: DRINKING AND DEPOSITION IN LATE IRON AGE SOUTH-EAST BRITAIN

Summary. This paper considers the role of pottery in the Late Iron Age to Roman transition in south-east Britain. Traditional concern with the significance of Continental imports is rejected in favour of a more holistic and bottom-up approach giving equal emphasis to locally made forms and imports in complete assemblages. Several stages of inter-site correspondence analysis are conducted on a range of sites and assemblages in the region. Patterning pertaining to the use and deposition of both imported and local pottery vessels can be seen to contradict simplistic models for 'Romanization before conquest'. The main conclusions include evidence for the selective disposal of drinking vessels and table wares in pits, the likely widespread consumption of beer as opposed to wine, and the implied importance of indigenous social practices such as feasting and communal drinking.