Construction and safety aspects for the arrangement of mobile explosive deposits

The execution of the blasting works involves the management of the problem of storage of explosive materials. This aspect is easier to solve in the case of mines activities with long exploitation time and where storage capacities are arranged, according to the legislation that provides constructive and safety criteria depending on the type and quantity of explosive materials stored. In the case of isolated blasting works, those for road construction, building demolition, underwater or forestry, etc., storage facilities must be arranged for shorter periods of time and smaller capacity, but which must comply with security, environmental and risk requirements, such as high-capacity deposits with long duration of activity. Considering that for the execution of such blasting works, the national legislation provides the possibility of arranging temporary explosive depots, of small capacity, but without specifying the constructive details and the necessary safety requirements to be observed, mentioning only that they must be executed on the basis of a specialized project. This paper presents a series of tests conducted by INSEMEX, in order to establish recommendations regarding the constructive and safety requirements that must be observed when designing and building mobile explosive depots.

Quantitative evaluation of the relationship between physical parameters and building demolition or adaptation outcomes

Building adaptation and re-use can contribute to a circular and sustainable built environment, as existing buildings are adapted and the need for new construction materials is reduced. The “adaptability” of buildings has been widely studied; however, few of these studies are quantitative. This paper uses Artificial Neural Networks (ANN) and Logistic Regression (LR) models to explore relationships between the physical features of buildings and their demolition or adaptation outcomes. Source data were taken from 59 buildings that were either demolished or adapted in the Netherlands. After the models were created and validated, a series of sensitivity studies were conducted to evaluate relationships between physical parameters and building outcomes. The physical parameter with the strongest relationship to adaptation outcomes was demountability (ease of removal) of building service elements. The quantitative results were then compared to results from an adjacent qualitative study. The relationships observed from the quantitative sensitivity studies align well with the qualitative observations.

Self-Compacting Concrete Properties of Recycled Coarse Aggregate

Self-compacting concrete, which is characterized by its capacity to flow, can also consolidate under its weight. Hardened concrete from concrete building demolition can be used to partially replace natural coarse aggregate in self-compacting concrete. The current study compares the properties of self-compacting concrete with 0 percent, 25%, 50%, 75%, and 100% substitution of recycled coarse aggregate in the fresh and hardened states. The evolution of passing ability properties using the L-box test, filling ability properties using the slump cone test, and segregation properties using the V-funnel test are also included. Compression, tension, and flexural strength are all checked for hardened properties. Rapid chloride permeability and sorptivity tests are used to assess durability. The experimental program revealed that at RCA utilization levels of 25% to 50%, little to no negative impact on power, workability, or durability properties was observed.

Quantum of Building Demolishied Debris Associated with Urban Road Construction in Gombe City, Nigeria

Demolition activity is deeply embedded in the urban system. In recent times, infrastructural development in Nigeria’s major cities has led to increase in road construction activities associated with demolition of hundreds of houses from which millions of tons of Demolition Waste have been generated. However, it is widely reported in many studies globally that demolition debris is such waste that can be re-used. Though, this is not the case in Gombe due to paucity of information on its composition, size and quantities. Hence, the objective of this study is to determine the volumetric composition of generated demolition debris in Gombe City with a view to knowing the potential quantities available for re-use. The study used both qualitative and quantitative design approach. A simple random sampling technique was employed to select 13 roads which were sub-divided in to Lot 1 (8.33km) and Lot 2 (15.04km) and the period of 2011-2014 was considered for the study. Primary data kept by actors and authorities for the compensation assessment which do not refer to demolition debris quantities were used as the bases for extraction of quantities. Handheld (GPS) instrument was used in establishing coordinates; photographs were taken from different locations showing demolition activities taking place and composition of different materials debris. Results revealed that a total of 1,271 structures were evaluated after partially or fully demolished for street widening and/or to pave way for new road construction, in addition a total volume of 129,993.57m3 of Demolished Debris was generated which composed of 10.00% Concrete, 60.30% Sandcrete and 29.69% clay/mud. In conclusion, there exist huge quantities of building demolition debris from street widening and/or new road construction in Gombe city which can be put in to re-use as a component of urban road construction, where properly managed will go a long way to reducing environmental adverse effect due to excessive exploitation for new material.

STUDY ON SAFETY OF PULLING DOWN COLUMNS IN BUILDING DEMOLITION

When walls and columns are demolished during the demolition of buildings in Japan, the lower parts of the walls and columns are cut, after which they are pulled down. This method is called the fall-down method. However, the amount of cutting required is unknown. If a worker cuts the columns too deeply, the walls and columns will collapse and may crush the worker. In this study, the fall-down test of columns was carried out to assess the safety of cutting the lower part of columns. The parameters of the test included the pattern of cutting the lower part of columns and the material properties of the model. In addition, the position of the neutral axis was examined by numerical analysis. The results showed that the cutting pattern involving leaving the main reinforcement at the front of the fall-down and cutting the concrete near the neutral axis is safe at demolition sites. In contrast, the cutting pattern with one row of main reinforcement at the front was unsafe and could potentially lead to premature collapse. Columns at demolition sites should not be cut by this latter cutting pattern. The test and the analysis in this study reproduce the demolition site, and the results of these be widely applied in the actual demolition site.

A novel application of building demolition waste for removal benzene from aqueous solutions

A novel application of building demolition waste for removal benzene from aqueous solutions. In this research, demolition waste from buildings has been studied for possible use as benzene removal adsorbent from aquatic solution. The effect of adsorbent dosage, contact time, initial benzene concentration, and initial pH on benzene adsorption capacity have been investigated in the batch adsorption experiments. The adsorption effects initially happened very rapidly and achieved equilibrium within 180 min. Benzene removal was observed to decrease by an increase in the initial concentration of benzene of 300–700 mg·L–1, an increase in the adsorbent dose of 0.4–2.4 g per 100 mL, where an optimum adsorbent dose equal to 1.2 g per 100 mL was found. The potential of adsorption increases with pH 3.0–7.0 to reach the maximum removal efficiency at pH 6.0. The findings showed that equilibrium data were adequately adapted and correlated with the Freundlich isotherm models. The average percentage of the removal at room temperature was about 98%. Results suggest that building demolition waste can be used effectively in industrial wastewater treatment for the removal of aromatic hydrocarbon, benzene, as a low-cost option.

Seismic performance of a retrofitted heritage unreinforced masonry building during the 2010/2011 Canterbury earthquakes

The Heritage Hotel (formerly Old Government Buildings) is one of the architectural heritage icons of Christchurch, New Zealand. Seismic retrofitting was undertaken on the structure in 1995 to achieve the earthquake loading provisions of the 1992 standard for design loadings (NZS 4203:1992). This building is a distinguished 1909 unreinforced masonry Italian High Renaissance palazzo building. The retrofit work included the installation of new lateral load-resisting structural systems, refurbishment of individual building elements, and partial building demolition with a total cost of approximately NZ$3.75 million. Detailed observations following the 2010/2011 Canterbury earthquakes showed that the building was subject to only minor damage during the September 2010 earthquake, whereas the February 2011 event caused some damage to exterior stonework and flooding in the basement due to liquefaction. This damage was easily repaired, and the building was fully functional by September 2013. Reported herein are details showcasing the success of the seismic retrofit and post-earthquake performance observations.