Evaluation of Foundation Settlement under Various Added Loads in Different Locations of Iraq Using Finite Element

Settlement is an important criterion in the design of the foundations. It is classifying into immediate (or elastic) settlement and consolidated settlement (primary and secondary). The factors that affect the shallow foundation settlement are the applied loads, soil stiffness, and geometric shape of foundation. Calculations of settlement depend on the parameters of soil which can be obtained from field and laboratory tests. Field and laboratory tests were conducted for twenty three sites in three different regions in Iraq (Mosul, Baghdad, and Basrah). In this research, field and laboratory tests results adopted for two sites from each region depended on the maximum and minimum bearing capacity values. Settlement for each site was calculated using numerical (mathematical) calculations and PLAXIS software under different added loads. The results of settlements beneath the foundation were competing for the sites with maximum value of bearing capacity in Mosul;Baghdad and Basrah. Also, the comparison conducted for sites of minimum bearing capacity value and the results showed different settlement values of each site. The change of settlement values under different loads was linearly in the six sites using numerical (mathematical) calculations. While, the settlement values obtained from PLAXIS software for sites with maximum bearing capacity value showed that Mosul site had the highest value due to the type of soil layers and the difference models of soil used in the software. Basrah site had a settlement value higher than Baghdad site due to the soil layers of sand type only. PLAXIS results for sites with minimum bearing capacity showed that for Basrah site the soil went to failure. While, the settlement values for Mosul and Baghdad sites were close to each other due to have nearly same soil layers. Therefore, high rise buildings could not be used in some sites. Also, soil in some locations and under some added loads needed to be improved before the implementation of any constructions.

Effect of Bearing Capacity on Designing Foundations in Iraq Using STAAD Pro-v8i

Most of Iraqi soil is classified as Quaternary deposits, especially in the Mesopotamian plain and tributaries of the River Tigris. Soil varies from north to south of Iraq. These differences in soil affected the process to select the suitable type of foundation. This research is to study the effect of bearing capacity on shallow foundations in different regions of Iraq. Seventy nine samples were collected from 23 boreholes at three different locations (Mosul at the North, Baghdad at the middle and Basrah at the south of Iraq). The samples were collected at varying depth between 1 to 24 m. They were subjected to the following testes: Atterberg limits, sieve and hydrometers, consolidation, direct shear, unconfined compression and the filed (SPT test). The values of the bearing capacity parameters ( and c) were obtained from the above tests. The results obtained were used in the application of the general equation of the bearing capacity. Then, the model of a building was designed (two floors, with mat foundation type) using STAAD Pro software. The average values of bearing capacity in each region were applied in the program (Mosul = 177 KPa, Baghdad = 125 KPa and Basrah = 84 KPa). In addition, the worst bearing capacity values were also used for the three regions (Mosul = 77 KPa, Baghdad = 68 KPa and Basrah = 24 KPa). The results obtained from the average and worst bearing capacity indicated that for Mosul, we could use shallow foundation (spread and mat used if there was basement) for different areas and for buildings with many stories. For Baghdad region, shallow foundation was more suitable for building not higher than five stories. Finally, for Basrah region, shallow foundations were an appropriate selection, but for most areas deep foundation was the right choice.

The Need to Develop a Building Code for Iraq

Building Code is a legal document that provides a minimum level of safety and health for the constructions to make the public live in safe buildings. People recognize the importance of constructing the buildings in safe conditions, since the dawn of civilization. Many countries around the world were facing different kind of disasters such as fires, earthquakes, etc. These disasters made builders develop methods for safe construction to avoid any disaster. Later, these developments became codes and standards. Since the middle of the last century many countries established its local codes. This research represented a review of the importance of the codes with a short history for them. Furthermore, reviews for some national codes (Egyptian, Syrian and Arabia Saudi) were done as well as comparison between load’s correction factors, geotechnical requirements and materials used in concrete. Most of the national codes were highly based on the ACI, British and Germany codes and standards. In addition, a review and comparison were presented for International codes (American (ACI) and European (EC)) through a case study. EC code is becoming more common for the world. Eurocode gives more flexibility to the user to employ their own standards (national annex). To find the best suitable foundation design to be used in Iraq and the differences when using the American and European codes, a building model was designed and analyzed using STAAD Pro., and SAFE softwares for three locations (Mosul, Baghdad and Basrah). The combination loads used in the two softwares were for ACI and EC codes. Results obtained were very similar. The type of foundation to be chosen for Mosul location is spread or continuous. For Baghdad location the suitable type is raft and for Basrah the choice is raft and piles. In view of the fact that Iraq has no national code, engineers and designers were depending on the ACI and British codes and standards. It is very important to have an Iraqi code because it will improve the quality and safety of the design and construction of buildings as well as its economic value.

Effect of Material Used in Concrete Mixture on the Foundation Stresses on Soil

Sustainable design, green architecture and sustainable construction are new methods for design and construction that are employed for environmental and economic challenges. Clay and bricks proved as sustainable building materials. In this paper, crush brick in the concrete mixture instead of normal coarse aggregate will be used. STAAD Prov8i software was applied for the designed of a hypothetical building in different sites of the three locations in Iraq (Mosul at the north, Baghdad at the center and Basrah at the south). The input model data used in the software were depending on the field and laboratory tests done for twenty three sites in the three locations of Iraq. Concrete properties values were used in the software for concrete mixture with crushed bricks. The results values of base pressure obtained from the software were low for the three locations. The maximum values of base pressure under the foundation for both the average and the minimum bearing capacity values for Mosul region for the normal strength concrete and air-entrained were (94, 84) kPa and (91, 82) kPa respectively, for Baghdad region were (89, 82) kPa and (86, 81) kPa respectively. Finally, for Basrah, the results for the base pressure were (84, 77) kPa and (82, 76) kPa, respectively. The results values of the base pressure were less for all locations compared with the base pressure values obtained from a previous work for the same locations. The use of crushed brick as aggregate in the concrete mixture is economical due to its availability as local material and it is durable materials with low weight.

Estimation of Settlement under Shallow Foundation for Different Regions in Iraq Using SAFE Software

Foundation design must satisfy limited values of settlement. Settlement is an essential criterion in the design process of shallow foundations. To calculate the settlement under different types of shallow foundations, 79 samples were taken from twenty-three sites distributed in three regions: Mosul, Baghdad and Basrah in the northern, central and southern parts of Iraq. Field and laboratory tests were performed to obtain the strength parameters to calculate the bearing capacity. The results obtained for the bearing capacity were used in SAFE software. The software was used to design and analyze the foundation and to calculate the settlements under two types of foundations (raft and continuous) for the three regions. Average and minimum values of bearing capacity were used. The software used subgrade reaction modules values for the design and analysis. According to the results, the suitable, safe and economical type of foundation to be used in Mosul, Baghdad and Basrah regions for the average value of bearing capacity is the continuous type for the first two regions while the raft type is recommended for Basrah region. In case that the minimum bearing capacity values are used, raft foundation is recommended for Mosul and Baghdad. While deep foundation is the suitable type of foundation for Basrah region.