Seismic performance of non-structural components and contents in buildings: an overview of NZ research

This paper summarizes the research on non-structural elements and building contents being conducted at University of Canterbury in New Zealand. Since the 2010-2011 series of Canterbury earthquakes, in which damage to non-structural components and contents contributed heavily to downtime and overall financial loss, attention to seismic performance and design of non-structural components and contents in buildings has increased exponentially in NZ. This has resulted in an increased allocation of resources to research leading to development of more resilient non-structural systems in buildings that would incur substantially less damage and cause little downtime during earthquakes. In the last few years, NZ researchers have made important developments in understanding and improving the seismic performance of secondary building elements such as partitions, facades, ceilings and contents.     

Overcoming source limitations in drainage delineation by combining the streams of toposheet and DEM in river morphometric studies

A potential head ward retreat landslide area was identified in Munnar, a hill station in Western Ghats of Kerala, India. This imminent landslide was suspected to be formed in three different stages viz., evolution of plateau region, upliftment of the plateau region and the consequent slope modification which ultimately facilitated landslide occurrence. Geophysical study through vertical electrical sounding reveals that more than 11 m thick soil is still left in an overhanging position in the crown portion of the landslide and the thickness continues to the top of that ridge. In the event of high rainfall, the land can fail as there is no toe support, and the slope angle is >40º. This area is adjacent to a college building and in the event of any further landslide, the consequence will be high. Slope stability analysis using one-dimensional infinite slope stability model reveals that the entire area occupied by the college and the adjacent areas are unstable even in dry conditions. Rainfall threshold analysis shows that the landslide occurred due to very high amount of a 5-day antecedent rainfall rather than a daily rainfall during the monsoon. All these point towards a pressing requirement of landslide management practices in this area. This study also attempts to suggest a few management practices to minimize the effect of landslides.     

Chromium(VI) adsorption by <Emphasis Type="Italic">Codium tomentosum</Emphasis>: evidence for adsorption by porous media from sigmoidal dose–response curve

Adsorption of Cr(VI) using native and chemically modified marine green macroalgae Codium tomentosum biomass and its adsorption kinetics were studied under specific conditions. Maximum Cr(VI) removal occurred at pH 2 for both untreated and acid-treated biomass. However, base-treated biomass exhibited maximum adsorption at pH 6 due to the hydrolysis of methyl esters present in the cellulose, hemicellulose and lignin molecules resulting in carboxyl groups (COO^?) on the surface. The effect of adsorbent dose revealed that untreated and acid-treated biomass follows Henry’s linear isotherm, while base-treated biomass exhibited sigmoidal curve indicating energetic heterogeneity on the adsorbing surface. The monolayer adsorption capacity of untreated, acid-treated and base-treated biomasses was 5.032 ± 0.644, 5.445 ± 0.947, 3.814 ± 0.559 mg g^?1, respectively. Adsorption was found to follow Ho and McKay’s pseudo-second-order kinetic model with decreasing pseudo-second-order rate constant (K ₂, g mg^?1 min^?1) of 0.088 ± 0.037 (acid-treated), 0.019 ± 0.003 (untreated) and 0.012 ± 0.003 (base-treated).     

Stability investigation of hill cut soil slopes along National highway 222 at Malshej Ghat,Maharashtra

The section of about 12 km of National highway 222 passing through the Malshej Ghat experience frequent slope failure due to complex geological condition, heavy rainfall and slope geometry. The area is part of Western Ghat Deccan trap and slope masses are made of basalt and its weathered crust (debris/soil). The soil slope failure problem mainly occur in rainy seasons due to induced pore water pressure and reduced strength of the slope mass. The present study has been carried out to investigate the slope forming material and assess the stability of soil slopes by numerical approach. For the identification of the vulnerable zones, field study has been carried out and five vulnerable soil slopes identified namely MGS1, MGS2, MGS3, MGS4 and MGS5 on the basis of degree of weathering and slope geometry. The laboratory experiments were carried out to determine the strength properties of the geomaterials. All the input variables acquired from the field and laboratory experiments have been used for numerical simulation, which was performed with the help of limit equilibrium method (LEM) and finite element method (FEM). Numerical analysis provides understanding of the slope behaviour and illustrates that MGS1 and MGS3 are stable slopes, MGS2 and MGS4 are critically stable, whereas, slope MGS5 is unstable. This study recommend the protection of soil slopes and suggest that more detailed investigation is required for long term remedial measures to prevent risk of damage in Malshej Ghat.     

Hydrochemical characteristics of groundwater in the plains of Phalgu River in Gaya, Bihar, India

Assessment of groundwater quality is essential to ensure sustainable use of it for drinking, agricultural, and industrial purposes. The chemical quality of groundwater of Gaya region has been studied in detail in this work to delineate the potable groundwater zones. A total of 30 groundwater samples and 2 surface water samples were collected in and around Gaya district of Bihar. The major cations follow the trend: Ca²⁺?>?Mg²⁺?>?Na⁺?>?K⁺. The domination of calcium ions in the groundwater is due to weathering of rocks. The K⁺ ranged between 0.2 and 47.95 ppm, suggesting its abundance the below desired limit; but some samples were found to be above permissible limit. K⁺ weathering of potash silicate and the use of potash fertilizer could be the source. The major anions abundance followed the order HCO ₃ ^? ?>?Cl^??>?SO ₄ ^2? ?>?NO ₃ ^? ?>?PO ₄ ^3? . Dissolution of carbonates and reaction of silicates with carbonic acid accounts for the addition of HCO ₃ ^? to the groundwater and oxidation of sulphite may be the source of SO ₄ ^2? . Principal component analysis was utilized to reflect those chemical data with the greatest correlation and seven major principal components (PCs) representing >80 % of cumulative variance were able to interpret the most information contained in the data. PC1, PC2 and PC3 reflect the hydrogeochemical processes like mineral dissolution, weathering and anthropogenic sources. PC4, PC5, PC6 and PC7 show monotonic, random and independent relationships.     

Sensitivity Analysis of Coal Rib Stability for Internal Mine Dump in Opencast Mine by Finite Element Modelling

The present paper discusses the impact of the geometrical parameters of the coal rib and the mine dump on the stability of the coal rib. The geometrical parameters such as the slope angle, the height of dragline dump, the height of main dump, the gradient of seam and the thickness of coal rib have been considered as input to the numerical model for the stability analysis of the coal rib. Sensitivity analysis has been performed based on the results of the analysis in term of factor of safety of the coal rib. The input parameters have been classified in terms of significance (i.e. very high significance, high significance medium significance and low significance). The factor of safety is more influenced by highly significant parameters. The height and the slope angle of dragline dump and the thickness of the coal rib are highly significant parameters for the stability of the coal rib. The gradient of the seam is a medium significant parameter whereas, height of main dump and the number of dragline cut dump are low significant parameters for stability of coal rib.     

Prediction of Uniaxial Compressive Strength,Tensile Strength and Porosity of Sedimentary Rocks Using Sound Level Produced During Rotary Drilling

The main purpose of the study is to develop a general prediction model and to investigate the relationships between sound level produced during drilling and physical properties such as uniaxial compressive strength, tensile strength and percentage porosity of sedimentary rocks. The results were evaluated using the multiple regression analysis taking into account the interaction effects of various predictor variables. Predictor variables selected for the multiple regression model are drill bit diameter, drill bit speed, penetration rate and equivalent sound level produced during rotary drilling (L _eq). The constructed models were checked using various prediction performance indices. Consequently, it is possible to say that the constructed models can be used for practical purposes.