Eccentric installation of splice plates for compressive strength improvement of rectangular hollow section braces

Steel hollow section members are often applied as bracing in steel structures. Field-bolted connections of the slotted-in single splice plate and the gusset plate are popular because of their ease of construction. However, eccentricity between the splice and gusset plate axes reduces the compressive strength of the brace. This study proposes compressive strength improvement of rectangular hollow section braces using eccentrically installed splice plates such that the gusset plate axis coincides with the brace axis. To demonstrate the efficacy of the proposed concept, four compressive loading test results are examined in this study. Test results reveal the influences of splice plate eccentric installation on the brace compressive strength, the out-of-plane displacement, and the strain distribution. The proposed concept is effective for the brace with stiffened splice plates for inducing overall buckling with plastic hinges in the gusset plates. Variation of compressive strength is finally discussed based on the discrepancy between the brace axis and the axis of the plates in which the plastic hinges form at the overall buckling mode ends.     

First-Aid Transportation by Hovercraft in a Disaster

Transportation is one of the most important and urgent tasks in a disaster, e.g., earthquake or flood. Trains, trucks and cars are very restricted by destruction of rail and road, bridges and buildings fall down, flood waters and thick mud, landslides, cracks, level differences, severe traffic jam etc. Sunken objects in the water and damages of quays prevent ships from reaching harbors. The situation remains days, weeks and even months.Hovercraft can run on almost every surface: ground, water surface, mud, sands, grits, weeds etc. The performance is very favorable in the first-aid transportation in a disaster.A middle size hovercraft with payload of 2–3 tons is suitable for first-aid work in a disaster. The amount of load is appropriate for loading and unloading by manpower without using a special loading machine. Small loads with frequent return trip are desirable to fulfill needs that are changing from time to time. A system of first-aid transportation by a number of hovercraft of middle size is proposed in this paper as an additional system of transportation to existing ones. The system is very useful for first-aid transportation in a disaster.A simulation of hovercraft transportation was carried out after the Kobe Earthquake in 1995 as an example. We assume that 20 hovercraft of middle size are operated from 6 bases just outside of the disaster area to 12 destinations in the area. The result shows that they can transport up to 1,200 tons goods in a day in addition to those of conventional transportation means without disturbing them.