Geotechnical assessment strategy for bridge maintenance – case study.

This paper presents a practical strategy used to conduct a geotechnical assessment, drawing principally on a maintenance work carried out recently for Rashwood Interchange which carries the M5 Motorway over the A38. The bridge, which was constructed in the early 1960s, had experienced long-term settlement attributed to historical brine pumping activities in the proximity of the bridge area. In planning for its maintenance work several issues challenged the geotechnical assessment, including the review of settlement history and mining instability in the area, the exploitation of as-built data records and the determination of foundation response to additional loading during the bridge repair. The paper presents how these complex challenges were approached, yet using simple procedures and common design tools. The procedures are also applicable to other infrastructure maintenance projects, particularly in transportation geotechnics.N/

Measurements of Distributed Strain During Impact Pile Driving

This paper reports the use of optical Fibre Bragg Grating (FBG) sensors to monitor the stress waves generated below ground during pile driving, combined with measurements using conventional pile driving analyzer (PDA) sensors mounted at the pile head. Fourteen tubular steel piles with a diameter of 508 mm and embedded length to diameter ratios of 6 to 20 were impact driven at an established chalk test site in Kent, UK. The pile shafts were instrumented with multiple FBG strain gauges and pile head PDA sensors, which monitored the piles’ responses under each hammer blow. A high frequency (5 kHz) fibre optic interrogator allowed a previously unseen resolution of the stress wave propagation along the pile. Estimates of the base soil resistances to driving and distributions of shaft shear resistances were found through signal matching that compared time series of pile head PDA measurements and FBG strains measured below ground surface. Numerical solutions of the one-dimensional wave equation were optimised by taking account of the data from multiple FBG gauges, leading to significant advantages that have potential for widespread application in cases where high resolution strain measurements are made

New fossil remains of Homo naledi from the Lesedi Chamber, South Africa

The Rising Star cave system has produced abundant fossil hominin remains within the Dinaledi Chamber, representing a minimum of 15 individuals attributed to Homo naledi. Further exploration led to the discovery of hominin material, now comprising 131 hominin specimens, within a second chamber, the Lesedi Chamber. The Lesedi Chamber is far separated from the Dinaledi Chamber within the Rising Star cave system, and represents a second depositional context for hominin remains. In each of three collection areas within the Lesedi Chamber, diagnostic skeletal material allows a clear attribution to H. naledi. Both adult and immature material is present. The hominin remains represent at least three individuals based upon duplication of elements, but more individuals are likely present based upon the spatial context. The most significant specimen is the near-complete cranium of a large individual, designated LES1, with an endocranial volume of approximately 610 ml and associated postcranial remains. The Lesedi Chamber skeletal sample extends our knowledge of the morphology and variation of H. naledi, and evidence of H. naledi from both recovery localities shows a consistent pattern of differentiation from other hominin species.SP201

Expanding the clinical phenotype of individuals with a 3-bp in-frame deletion of the NF1 gene (c.2970_2972del): an update of genotype–phenotype correlation

Purpose: Neurofibromatosis type 1 (NF1) is characterized by a highly variable clinical presentation, but almost all NF1-affected adults present with cutaneous and/or subcutaneous neurofibromas. Exceptions are individuals heterozygous for the NF1 in-frame deletion, c.2970_2972del (p.Met992del), associated with a mild phenotype without any externally visible tumors. Methods: A total of 135 individuals from 103 unrelated families, all carrying the constitutional NF1 p.Met992del pathogenic variant and clinically assessed using the same standardized phenotypic checklist form, were included in this study. Results: None of the individuals had externally visible plexiform or histopathologically confirmed cutaneous or subcutaneous neurofibromas. We did not identify any complications, such as symptomatic optic pathway gliomas (OPGs) or symptomatic spinal neurofibromas; however, 4.8% of individuals had nonoptic brain tumors, mostly low-grade and asymptomatic, and 38.8% had cognitive impairment/learning disabilities. In an individual with the NF1 constitutional c.2970_2972del and three astrocytomas, we provided proof that all were NF1-associated tumors given loss of heterozygosity at three intragenic NF1 microsatellite markers and c.2970_297

An Analytical Solution for the Consolidation around a Laterally Loaded Pile

This paper presents a closed-form analytical solution for the consolidation of soil around a laterally loaded pile, assuming the soil skeleton deforms elastically and under plane strain conditions. The problem is idealized as a circular rigid disk surrounded by a deformable soil zone. Drainage is assumed to occur at the boundary of the assumed zone of deformable soil around the pile. The response around the pile is obtained using an uncoupled consolidation analysis. The solution for the governing equation of excess pore water pressure is found by using the separation of variables technique. Expressions for the initial excess pore water pressure distribution are derived from the mean total stress changes given by the elastic solution. Curves showing decay of the excess pore water pressure with time, and also the variation of pile displacement, are plotted in nondimensional form. The parameters that affect the displacement prediction are illustrated and discussed. Comparison with three-dimensional analysis of a laterally loaded pile shows that the two-dimensional analysis can reasonably predict the consolidation process along the shaft of the pile