Read some of our older abstracts from across the sectors we serve.
Comparative Tests on Aggregate Concrete Blockwork Walls Containing Wind Posts and Bond Beams
The use of steel wind posts to subdivide large panels which are subjected to significant wind loads is common. However they do create issues of cost, correct installation, tying and fire protection. An alternative solution for aggregate blockwork is to introduce horizontal beams at intervals up the height of the wall. This paper describes a programme of tests on eight walls either subdivided by bond beams, by a box section wind post or an integral wind post. Sufficient has been done to demonstrate the satisfactory performance of the bond beam approach and a design procedure has been developed.
Restoration of Historic Brickwork Case Study: The Round Foundry, Leeds, UK
The Round Foundry in Leeds was the first site in the UK where all of the trades were brought together for the production of static steam engines. The buildings, eleven in total, were built in the nineteenth century, the latest in around 1875. They included cast and wrought ironwork and massive timber roof trusses, all of which were of interest; however this paper will focus on the brickwork fabric. The buildings were largely derelict but there was a desire to bring them back into use as apartments, offices, restaurants and bars. This paper describes the investigation into the properties of the brickwork and how the site was developed to be suitable for modern use. Of particular relevance was the compressive strength of the walls of what had been at one time the massive machine assembly hall. The buildings were listed as being of historical interest and hence retention was a priority but this was in circumstances where local damage due to frost, water, salts and movement was evident. Consequently the desire to retain appeared at times to conflict with need to make commercial decisions about the value and earning potential of the buildings in the future.
The Development of Masonry Reinforced by Bond Beams and Bond Columns to Resist Lateral Load
In 2009 the Design Guide for Masonry Reinforced by Bond Beams to resist Lateral Loads was published. This represented the culmination of a series of tests on full size walls, small beams and low height walls. The tests demonstrated that large walls could be subdivided into smaller panels by the use of bond beams and that the lateral load resistance was considerable and comparable to walls subdivided by wind posts. The system has now been further developed to include the use of reinforced hollow blockwork columns, which enables walls to be subdivided by both horizontal and vertical reinforced elements. This paper describes the column tests and the development of a revised and extended design guide. A major application of the system is at the Aquatic Centre for the 2012 Olympic Games in London. In this iconic structure the internal blockwork walls are up to 7 m high and are required to accommodate numerous openings for services. The system enables this to be done in an elegant and efficient way and the paper describes how this was achieved.
Testing of Reinforced AAC Walls Under Lateral and Racking Loads
Reinforced AAC panels in the UK have been used in past, but these tended to be acting as roof units and to a limited extent floor units, with walling elements occasionally used horizontally as fire walls or thinner vertical elements for partitions. In more recent times, their use in housing has been explored as a series of vertical storey height, solid wall elements (each element being 600mm wide) to form the outer fabric of construction. In this form of construction a thickness of 200mm will act as the main load-bearing component of the structure as well as making a significant contribution to the overall thermal performance of the building.
Cleanliness and Microstructural Issues Related to Additive Layer Manufactured Porous Surface Structured Titanium Medical and Dental Implants - presented at the Titanium World Conference in San Diego - August 2015
Porous-layer coated titanium medical and dental implants have been the industry standard for several decades. Sintered-on wire or beads, as well as plasma sprayed titanium coatings, have been the most common methods for creating a porous surface structure for effective osseointegration in these devices. Efficacious methods have evolved over the years to ensure cleanliness of the unique porous structure of the final device. New additive layer manufacturing (ALM) techniques are being utilized to produce titanium alloy implant devices with integrated porous surface structures. ALM processes utilizing Electron Beam Manufacturing (EBM) and Direct Metal Laser Sintering (DMLS) produce varied and complex porous surface structures that present considerable challenges for appropriate cleaning. Images of these complex porous structures will be presented in both spatial and cross-sectional views using optical and scanning electron microscope (SEM) imaging. The types of residual contaminants seen on finished goods will be classified. In addition, cleanliness issues related to the shedding of particulate in the form of unfused metal powder particles will be addressed, as this continues to be an issue with ALM processing. The resulting microstructures from typical EBM and DMLS components have been examined and compared to devices manufactured by conventional wrought and casting methods. The effect of Hot Isostatic Pressing (HIPing) is also assessed with respect to particle shedding and microstructure.