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Edit Comment Close Premium member Presentation Transcript Slide 1: In the name of Allah, the compassionate, the merciful FOUNDATION PROBLEMS : FOUNDATION PROBLEMS Sohail Kibria M.Sc. Civil Engg. General Manager, Geotech. & Geo-environmental Engg. Division, NESPAK Slide 3: PROPERLY DESIGNED, CONSTRUCTED & DURABLE FOUNDATIONS IN ALL GROUND CONDITIONS ENSURE SAFETY OF BUILDINGS AND THE HUMAN LIVES. Slide 4: MOST OF THE PROBLEMS IN FOUNDATIONS ARISE DUE TO PROBLEMATIC SOILS UNGLORIOUS ? : UNGLORIOUS ? THERE IS NO GLORY IN FOUNDATIONS ………….. Karl Terzaghi STEP CHILD NOTION : STEP CHILD NOTION IN CIVIL ENGG. PROJECTS, THE WORKS OF FOUNDATION ENGG. ARE OFTEN TAKEN AS A STEP CHILD; AND WHEN THE STEP CHILD GOES TO TAKE REVENGE, THE RESULTS ARE VERY NASTY …………. Karl Terzaghi WHAT ARE PROBLEM SOILS ? : WHAT ARE PROBLEM SOILS ? The soils that show abnormal behavior, not recognizable by routine soil testing i. e. by classification, strength, settlement and chemical testing are called problem soils. These soils possess undesirable engineering properties, that may badly affect the structures, if not attended properly. VARIOUS PROBLEM GROUND CONDITIONS IN PAKISTAN : VARIOUS PROBLEM GROUND CONDITIONS IN PAKISTAN Landslide Prone Areas Swelling/Shrinking Soils Dispersive Soils Collapsible Soils Liquefiable Soils Soft Ground/Fill Areas Sheared Clays Soils with Chemicals WHAT CAN THESE SOILS DO ? : WHAT CAN THESE SOILS DO ? SUDDEN / EXCESSIVE SETTLEMENTS TILTING / SINKING OF BUILDINGS CRACKS IN BUILDINGS COLLAPSE OF BUILDINGS CHEMICAL ATTACK ON FOUNDATIONS ADDITIONAL DIFFICULTIES IN PLANNING / DESIGN / CONSTRUCTION : ADDITIONAL DIFFICULTIES IN PLANNING / DESIGN / CONSTRUCTION Space restriction and design modifications Time constraints Resources constraints Excessive variation in ground levels / bedrock levels Abnormal changes in environments after construction Slide 11: PROBLEMATIC SOILS REQUIRE SPECIAL TESTS AND STUDIES FOR THEIR IDENTIFICATION AT SITE & IN THE LAB. SUBSEQUENTLY SPECIAL MITIGATIVE MEASURES WILL BE REQUIRED. WHERE LOCATED IN PAKISTAN ? : WHERE LOCATED IN PAKISTAN ? We can gain from the Chinese and Russian experiences of collapsible soils, Japanese experiences of landslides and liquefiable soils, Indian experiences of swelling soils etc. Some of the areas containing problematic ground conditions in Pakistan include landsliding problems in the northern parts of Pakistran, swelling soils at D .I. Khan, Chakwal, Dera Bugti, Khairpur etc., collapsible soils at Rawat, Hub, Sahiwal etc., liquefiable soils at Chashma, Kalabagh, Kot Addu, Muzaffargarh etc., dispersive soils at Turbat etc. and soft ground conditions in the historical cities like Lahore, Peshawar, Multan, Pakpattan etc. and in the cultivated lands. LANDSLIDE PRONE AREAS : LANDSLIDE PRONE AREAS CAUSES Unstable soils/rocks Water movement Earthquakes EFFECTS Sliding Total Destruction MITIGATION Stabilization of unstable slopes Construction to resist earthquakes Construction in safe areas Soft Ground/Dumped Fill : Soft Ground/Dumped Fill CAUSES Wet lands Agricultural sites Old dumped fills EFFECTS High settlements Cracking/damage of structures MITIGATION Bypassing Replacement Rigid Foundation system/Deep foundation system Prevent water ingress Swelling / Shrinking Soils : Swelling / Shrinking Soils CAUSES Presence of single and double layer minerals in soils attract water and swell Exposure of expansive soils supporting light structures to water EFFECT Map cracking on ground surface in dry weather Swelling with water, causing cracks in light buildings Heaving of floors and pavements Shrinkage will take place in expansive soils upon reduction in moisture MITIGATION Bypassing Replacing Preventing water ingress Rigid foundation system Pre-wetting Lime treatment Deeper foundations SWELLING CLAY MINERALS : SWELLING CLAY MINERALS IDENTIFICATION OF SWELLING SOILS : IDENTIFICATION OF SWELLING SOILS INDICATION OF DEGREE OF SWELLING : INDICATION OF DEGREE OF SWELLING SWELL MITIGATION AT GOMAL UNIVERSITY, D.I. KHAN : SWELL MITIGATION AT GOMAL UNIVERSITY, D.I. KHAN DISPERSIVE SOILS : DISPERSIVE SOILS CAUSES Presence of high Na ions in comparison to total quantity of Na, K, Ca & Mg ions EFFECTS Dispersion of soil grains even in still water Quick erosion of soils Loss of soil cover MITIGATION Provision of protective layer Provision of filters Addition of lime DISPERSIVE SOILS : DISPERSIVE SOILS COLLAPSIBLE SOILS : COLLAPSIBLE SOILS CAUSES In arid/ semi-arid areas, temporary bonds develop between soil grains. These bonds dissolve upon wetting and under pressure EFFECTS Sudden subsidence of soils upon wetting Damage to the buildings on such soils MITIGATION Prewetting Compaction Replacement Rigid Foundation Bypassing such soils Preventing water ingress COLLAPSIBLE SOIL GRAINS : COLLAPSIBLE SOIL GRAINS USBR COLLAPSE CRITERIA : USBR COLLAPSE CRITERIA COLLAPSE STUDY IN LAB. : COLLAPSE STUDY IN LAB. COLLAPSIBLE SOILS : COLLAPSIBLE SOILS RIGID FOUNDATIONS TO RESIST COLLAPSE OF SOILS : RIGID FOUNDATIONS TO RESIST COLLAPSE OF SOILS LIQUEFIABLE SOILS : LIQUEFIABLE SOILS CAUSES Fine to medium sands, under high groundwater table, develop very high pore water pressure under seismic / pulsating loads. EFFECTS The shear strength of soils becomes very low, as the pore pressure rises. Buildings may tilt, sink or get cracked. Loss of life may also occur. MITIGATION Ground improvement by various means Deep foundations Construction on raised ground GRAIN SIZE OF LIQUEFIABLE SOILS : GRAIN SIZE OF LIQUEFIABLE SOILS EVALUATION OF LIQUEFACTION POTENTIAL : EVALUATION OF LIQUEFACTION POTENTIAL DYNAMIC COMPACTION : DYNAMIC COMPACTION VIBROCOMPACTION : VIBROCOMPACTION GROUTING AND GRAVEL DRAINS : GROUTING AND GRAVEL DRAINS SHEARED CLAYS : SHEARED CLAYS CAUSES The presence of fissures causes low shear strength to mobilize at failure The main reason is overconsolidation and the stress relief EFFECTS Low shearing strength called residual strength is available for design Shearing may trigger sliding at low loads MITIGATION The presence of sheared clays can be taken care of, once it is indicated in the lab. Test results SOILS WITH CHEMICALS : SOILS WITH CHEMICALS CAUSES Unleached soils in arid areas Rise of groundwater table, rich in salts EFFECTS Sulphate attack on bricks / concrete Chloride attack on steel MITIGATION Use of appropriate cement Water proofing of substructures Use of rich / impervious concrete mixes Coating of steel SOME PROJECTS WITH PROBLEM GROUND CONDITIONS : SOME PROJECTS WITH PROBLEM GROUND CONDITIONS Gomal University, D. I. Khan Shah Abdul Latif Bhatai Univ., Khairpur Sialkot-Lahore Motorway Project Chashma Nuclear Power Plant Chashma Hydropower Project Galadari Cement Works, Hub Lucky Cement Project, D. I. Khan Akra Kaur Dam Project Pakistan Housing Project New Islamabad International Airport Project Lahore Ring Road Project Lai Expressway Project NUST Campus, Islamabad KKH Upgradation / Reconstruction Project MITIGATIVE RECOMMENDATIONS : MITIGATIVE RECOMMENDATIONS The following broad conclusions are drawn and recommendations are made for the design of safe buildings on problematic sites: For a building project, adequate amount of field and laboratory studies must be carried out to investigate the possibility of the presence of a problematic soil. In case, the presence of a problematic soil is confirmed, supplementary testing for quantification of the relevant parameters must be carried out. The most cost-effective remedial measures must be subsequently evolved, in keeping with the indigenous technology. The engineering institutions must consider launching a comprehensive research program, for a detailed study of problem soils and preparation of national guidelines, for the design of safe buildings in such conditions. THANK YOU : THANK YOU You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
FOUNDATION PROBLEMS rizwankhurram Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 639 Category: Entertainment License: All Rights Reserved Like it (3) Dislike it (0) Added: September 07, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: jecc69 (7 month(s) ago) Excellent work. Saving..... Post Reply Close Saving..... Edit Comment Close By: atharvienna (16 month(s) ago) good presentation i want to download Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Slide 1: In the name of Allah, the compassionate, the merciful FOUNDATION PROBLEMS : FOUNDATION PROBLEMS Sohail Kibria M.Sc. Civil Engg. General Manager, Geotech. & Geo-environmental Engg. Division, NESPAK Slide 3: PROPERLY DESIGNED, CONSTRUCTED & DURABLE FOUNDATIONS IN ALL GROUND CONDITIONS ENSURE SAFETY OF BUILDINGS AND THE HUMAN LIVES. Slide 4: MOST OF THE PROBLEMS IN FOUNDATIONS ARISE DUE TO PROBLEMATIC SOILS UNGLORIOUS ? : UNGLORIOUS ? THERE IS NO GLORY IN FOUNDATIONS ………….. Karl Terzaghi STEP CHILD NOTION : STEP CHILD NOTION IN CIVIL ENGG. PROJECTS, THE WORKS OF FOUNDATION ENGG. ARE OFTEN TAKEN AS A STEP CHILD; AND WHEN THE STEP CHILD GOES TO TAKE REVENGE, THE RESULTS ARE VERY NASTY …………. Karl Terzaghi WHAT ARE PROBLEM SOILS ? : WHAT ARE PROBLEM SOILS ? The soils that show abnormal behavior, not recognizable by routine soil testing i. e. by classification, strength, settlement and chemical testing are called problem soils. These soils possess undesirable engineering properties, that may badly affect the structures, if not attended properly. VARIOUS PROBLEM GROUND CONDITIONS IN PAKISTAN : VARIOUS PROBLEM GROUND CONDITIONS IN PAKISTAN Landslide Prone Areas Swelling/Shrinking Soils Dispersive Soils Collapsible Soils Liquefiable Soils Soft Ground/Fill Areas Sheared Clays Soils with Chemicals WHAT CAN THESE SOILS DO ? : WHAT CAN THESE SOILS DO ? SUDDEN / EXCESSIVE SETTLEMENTS TILTING / SINKING OF BUILDINGS CRACKS IN BUILDINGS COLLAPSE OF BUILDINGS CHEMICAL ATTACK ON FOUNDATIONS ADDITIONAL DIFFICULTIES IN PLANNING / DESIGN / CONSTRUCTION : ADDITIONAL DIFFICULTIES IN PLANNING / DESIGN / CONSTRUCTION Space restriction and design modifications Time constraints Resources constraints Excessive variation in ground levels / bedrock levels Abnormal changes in environments after construction Slide 11: PROBLEMATIC SOILS REQUIRE SPECIAL TESTS AND STUDIES FOR THEIR IDENTIFICATION AT SITE & IN THE LAB. SUBSEQUENTLY SPECIAL MITIGATIVE MEASURES WILL BE REQUIRED. WHERE LOCATED IN PAKISTAN ? : WHERE LOCATED IN PAKISTAN ? We can gain from the Chinese and Russian experiences of collapsible soils, Japanese experiences of landslides and liquefiable soils, Indian experiences of swelling soils etc. Some of the areas containing problematic ground conditions in Pakistan include landsliding problems in the northern parts of Pakistran, swelling soils at D .I. Khan, Chakwal, Dera Bugti, Khairpur etc., collapsible soils at Rawat, Hub, Sahiwal etc., liquefiable soils at Chashma, Kalabagh, Kot Addu, Muzaffargarh etc., dispersive soils at Turbat etc. and soft ground conditions in the historical cities like Lahore, Peshawar, Multan, Pakpattan etc. and in the cultivated lands. LANDSLIDE PRONE AREAS : LANDSLIDE PRONE AREAS CAUSES Unstable soils/rocks Water movement Earthquakes EFFECTS Sliding Total Destruction MITIGATION Stabilization of unstable slopes Construction to resist earthquakes Construction in safe areas Soft Ground/Dumped Fill : Soft Ground/Dumped Fill CAUSES Wet lands Agricultural sites Old dumped fills EFFECTS High settlements Cracking/damage of structures MITIGATION Bypassing Replacement Rigid Foundation system/Deep foundation system Prevent water ingress Swelling / Shrinking Soils : Swelling / Shrinking Soils CAUSES Presence of single and double layer minerals in soils attract water and swell Exposure of expansive soils supporting light structures to water EFFECT Map cracking on ground surface in dry weather Swelling with water, causing cracks in light buildings Heaving of floors and pavements Shrinkage will take place in expansive soils upon reduction in moisture MITIGATION Bypassing Replacing Preventing water ingress Rigid foundation system Pre-wetting Lime treatment Deeper foundations SWELLING CLAY MINERALS : SWELLING CLAY MINERALS IDENTIFICATION OF SWELLING SOILS : IDENTIFICATION OF SWELLING SOILS INDICATION OF DEGREE OF SWELLING : INDICATION OF DEGREE OF SWELLING SWELL MITIGATION AT GOMAL UNIVERSITY, D.I. KHAN : SWELL MITIGATION AT GOMAL UNIVERSITY, D.I. KHAN DISPERSIVE SOILS : DISPERSIVE SOILS CAUSES Presence of high Na ions in comparison to total quantity of Na, K, Ca & Mg ions EFFECTS Dispersion of soil grains even in still water Quick erosion of soils Loss of soil cover MITIGATION Provision of protective layer Provision of filters Addition of lime DISPERSIVE SOILS : DISPERSIVE SOILS COLLAPSIBLE SOILS : COLLAPSIBLE SOILS CAUSES In arid/ semi-arid areas, temporary bonds develop between soil grains. These bonds dissolve upon wetting and under pressure EFFECTS Sudden subsidence of soils upon wetting Damage to the buildings on such soils MITIGATION Prewetting Compaction Replacement Rigid Foundation Bypassing such soils Preventing water ingress COLLAPSIBLE SOIL GRAINS : COLLAPSIBLE SOIL GRAINS USBR COLLAPSE CRITERIA : USBR COLLAPSE CRITERIA COLLAPSE STUDY IN LAB. : COLLAPSE STUDY IN LAB. COLLAPSIBLE SOILS : COLLAPSIBLE SOILS RIGID FOUNDATIONS TO RESIST COLLAPSE OF SOILS : RIGID FOUNDATIONS TO RESIST COLLAPSE OF SOILS LIQUEFIABLE SOILS : LIQUEFIABLE SOILS CAUSES Fine to medium sands, under high groundwater table, develop very high pore water pressure under seismic / pulsating loads. EFFECTS The shear strength of soils becomes very low, as the pore pressure rises. Buildings may tilt, sink or get cracked. Loss of life may also occur. MITIGATION Ground improvement by various means Deep foundations Construction on raised ground GRAIN SIZE OF LIQUEFIABLE SOILS : GRAIN SIZE OF LIQUEFIABLE SOILS EVALUATION OF LIQUEFACTION POTENTIAL : EVALUATION OF LIQUEFACTION POTENTIAL DYNAMIC COMPACTION : DYNAMIC COMPACTION VIBROCOMPACTION : VIBROCOMPACTION GROUTING AND GRAVEL DRAINS : GROUTING AND GRAVEL DRAINS SHEARED CLAYS : SHEARED CLAYS CAUSES The presence of fissures causes low shear strength to mobilize at failure The main reason is overconsolidation and the stress relief EFFECTS Low shearing strength called residual strength is available for design Shearing may trigger sliding at low loads MITIGATION The presence of sheared clays can be taken care of, once it is indicated in the lab. Test results SOILS WITH CHEMICALS : SOILS WITH CHEMICALS CAUSES Unleached soils in arid areas Rise of groundwater table, rich in salts EFFECTS Sulphate attack on bricks / concrete Chloride attack on steel MITIGATION Use of appropriate cement Water proofing of substructures Use of rich / impervious concrete mixes Coating of steel SOME PROJECTS WITH PROBLEM GROUND CONDITIONS : SOME PROJECTS WITH PROBLEM GROUND CONDITIONS Gomal University, D. I. Khan Shah Abdul Latif Bhatai Univ., Khairpur Sialkot-Lahore Motorway Project Chashma Nuclear Power Plant Chashma Hydropower Project Galadari Cement Works, Hub Lucky Cement Project, D. I. Khan Akra Kaur Dam Project Pakistan Housing Project New Islamabad International Airport Project Lahore Ring Road Project Lai Expressway Project NUST Campus, Islamabad KKH Upgradation / Reconstruction Project MITIGATIVE RECOMMENDATIONS : MITIGATIVE RECOMMENDATIONS The following broad conclusions are drawn and recommendations are made for the design of safe buildings on problematic sites: For a building project, adequate amount of field and laboratory studies must be carried out to investigate the possibility of the presence of a problematic soil. In case, the presence of a problematic soil is confirmed, supplementary testing for quantification of the relevant parameters must be carried out. The most cost-effective remedial measures must be subsequently evolved, in keeping with the indigenous technology. The engineering institutions must consider launching a comprehensive research program, for a detailed study of problem soils and preparation of national guidelines, for the design of safe buildings in such conditions. THANK YOU : THANK YOU