Geotechnical investigators are among the first to assess the Geotechnical investigators are among the first to assess the Geotechnical investigators are among the first to assess the Geotechnical investigators are among the first to assess the are performed to ascertain the character and variability of the strata underlying the site of the proposed structure are performed to ascertain the character and variability of the strata underlying the site of the proposed structure are performed to ascertain the character and variability of the strata underlying the site of the proposed structure are performed to ascertain the character and variability of the strata underlying the site of the proposed structure and to assess those properties, which may affect the performance of the structur and to assess those properties, which may affect the performance of the structur and to assess those properties, which may affect the performance of the structur and to assess those properties, which may affect the performance of the structur construction. Deficient geotechnical investigations, faulty interpretation of results, or failure to portray results in a construction. Deficient geotechnical investigations, faulty interpretation of results, or failure to portray results in a construction. Deficient geotechnical investigations, faulty interpretation of results, or failure to portray results in a construction. Deficient geotechnical investigations, faulty interpretation of results, or failure to portray results in a clearly understandable manner may contribute to inappropriate designs; delays in construction schedules, clearly understandable manner may contribute to inappropriate designs; delays in construction schedules, clearly understandable manner may contribute to inappropriate designs; delays in construction schedules, clearly understandable manner may contribute to inappropriate designs; delays in construction schedules, construction modifications, and use of substandard borrow material, environmental damage to the site, post construction modifications, and use of substandard borrow material, environmental damage to the site, post construction modifications, and use of substandard borrow material, environmental damage to the site, post construction modifications, and use of substandard borrow material, environmental damage to the site, post construction remedial work, and even failure of a structure and subsequent litigation. Trenchless technology can be construction remedial work, and even failure of a structure and subsequent litigation. Trenchless technology can be construction remedial work, and even failure of a structure and subsequent litigation. Trenchless technology can be construction remedial work, and even failure of a structure and subsequent litigation. Trenchless technology can be defined as the use of con defined as the use of con defined as the use of con defined as the use of construction methods to install and repair underground infrastructure without digging a struction methods to install and repair unde...

Previous analysis showed that cavity size and number on one hand and combinations thickness affect the compressive strength of hollow sandcrete blocks. Series arrangement of the cavities is common but parallel arrangement has been recommended. This research performed a comparative analysis of the compressive strength of cavities of different configurations. The test thin plate distributes the load on the block and the hollow block is regarded as a two way slab. The results showed that at equal end-web to centre -web thickness (1:2) and total cavity volume the stresses in the parallel configuration were higher than those in series configuration. The minimum stresses in the series arrangement were lower than the corresponding values in the parallel arrangement. In addition, the maximum stresses in the series arrangement were lower than the corresponding values for parallel arrangement. The implication is that at same volume and number of cavities and web thickness, the series arrangement results induced least stress.

The relationship between cavity size and number on one hand and combinations of web thicknesses were investigated theoretically. The least number of cavities was 4 for end-web to centre web ratio of 1:2 at constant shell thickness with the least web thickness equal to 12.5mm. The effects of the number of cavities and web thickness on strength were also investigated. The test thin plate distributes the load on the block and the hollow block is regarded as a two way slab. One of the principal findings is that the variation of maximum stresses with the number of cavity is Gaussian for end-web to centre-web ratio of 1:1 but polynomial for 1:2. In addition, the lowest stress is induced when the end to centre ratio is one. The maximum stress, (21.5N/mm 2) occurred at the cavity length (a*) of 125mm for 3 cavities while the end (end centre) web thickness (t) was 25mm respectively. In order words, this combination should be avoided as it will lead to creation of highest stress in the hollow sandcrete blocks. The configuration which will result in least stress (0.5N/mm 2) is (a *, N, t) = (50mm, 4mm, 50mm). However, this combination also gave a high maximum stress (6.9N/mm 2) in a web, implying that the right choice of configuration should be rather the one that creates the smallest set of maximum stresses in all members. Overall, the best configuration is 2 cavities with web thickness 50mm for an end web to centre web ratio of 1:1 (3.3N/mm 2). The corresponding values for 1: 2 ratios are 3 cavities with 50mm shell thickness (4.8N/mm 2). The method presented showed meaningful insight could be investigating theoretically.

Soil stabilization using vibroflotation method requires material backfill for smooth operation of the process and effective densification. Backfill materials fill the voids created by the vibroflot and acceptable backfill is sand with less percentage of fines. This study assesses the suitability of Nsukka sand for backfill purpose in vibroflotation. Samples of Nsukka sand were tested in the laboratory for their physical, mechanical and electro-chemical properties. The suitability numbers (SN) were determined and a linear regression analysis carried out to correlate the values of SN with the properties of the sand. Tests results showed that Nsukka sand is "Good" backfill material for vibroflotation with a mean SN of 15. The samples indicated narrow percentage of fines value of 0.34-4.81% and are generally classified as poorly graded sand (SP) with mean fineness modulus of 2.12. They have low salt content with electrical conductivity values between 1090-1950µS/cm and mean pH and chloride content values of 6.8 and 98.5ppm respectively. Dry compaction test reveals mean MDD value of 1809kg/m 3 for standard Proctor compaction. Linear regression analysis reveals that SN is dependent on D10 and D30. The efficiency of the model was tested with separate results and the differences between the actual and the predicted SN were small and acceptable. This study concludes that Nsukka sand is a good material for vibroflotation densification.

ABSTRACTArch and conical roof trusses are employed when dealing with large span roof trusses. But a Arch and conical roof trusses are employed when dealing with large span roof trusses. But a Arch and conical roof trusses are employed when dealing with large span roof trusses. But a Arch and conical roof trusses are employed when dealing with large span roof trusses. But a geometrical shapes may lead to a better economical sections and a means of dealing with larger spans of roof truss geometrical shapes may lead to a better economical sections and a means of dealing with larger spans of roof truss geometrical shapes may lead to a better economical sections and a means of dealing with larger spans of roof truss geometrical shapes may lead to a better economical sections and a means of dealing with larger spans of roof truss that are not suitable for an arch or conical roof truss. Consequently, this paper examines the structural and that are not suitable for an arch or conical roof truss. Consequently, this paper examines the structural and that are not suitable for an arch or conical roof truss. Consequently, this paper examines the structural and that are not suitable for an arch or conical roof truss. Consequently, this paper examines the structural and economic economic economic economic viability of viability of viability of viability of arched arched arched arched conical roof truss conical roof truss conical roof truss conical roof truss the results showed that truss members were subjected to higher axial forces in 2D analysis than 3D analysis, which the results showed that truss members were subjected to higher axial forces in 2D analysis than 3D analysis, which the results showed that truss members were subjected to higher axial forces in 2D analysis than 3D analysis, which the results showed that truss members were subjected to higher axial forces in 2D analysis than 3D analysis, which will result to overdesign of the st will result to overdesign of the st will result to overdesign of the st will result to overdesign of the structural members and the attendant high construction cost. There are some ructural members and the attendant high construction cost. There are some ructural members and the attendant high construction cost. There are some ructural members and the attendant high construction cost. There are some variations observed in the axial forces for trusses located at edges of variations observed in the axial forces for trusses located at edges of variations observed in the axial forces for trusses located at edges of variations observed in the axial forces for trusses located at edges of located mid located mid located mid located mid----point between two point between two point between two point between two polygonal polygonal polygonal polygonal properties of the members as well as in the fabrication and installation cost. properties of the members as well as in the fabrication and installation cost. properties of the members as well as in the fabrication and inst...