[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-seo-650270-105":3,"detail-sidebar-cat-0-en-105":80,"doc-detail-650270-en":130},{"code":4,"msg":5,"data":6},0,"ok",{"site_id":7,"language":8,"slug":9,"title":10,"keywords":11,"description":12,"schema_data":13,"social_meta":73,"head_meta":75,"extra_data":77,"updated_unix":79},105,"en","example-geotechnical-report-recommendations-underpinning-magnum-helical-pile-foundations-underpinning-existing-foundations","Example Geotechnical Report Recommendations-Underpinning - MAGNUM Helical Pile Foundations - Underpinning Existing Foundations","","Underpinning is described as a method of supporting and stabilizing existing foundations using foundation piers or pile systems to address concerns about movement and to allow added loads. A recommended approach uses helical piles attached to existing concrete with steel brackets, highlighting benefits such as uplift resistance, minimal disruption, and low vibration. The document outlines helical pile sizing, engineering oversight, proof testing, bearing calculations with safety factors, corrosion treatment, lateral-load limitations, bracing requirements, placement tolerances, and torque-based installation and acceptance criteria.",{"@graph":14,"@context":72},[15,34,55],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/research-report/","Research & Report",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/example-geotechnical-report-recommendations-underpinning-magnum-helical-pile-foundations-underpinning-existing-foundations/650270/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/example-geotechnical-report-recommendations-underpinning-magnum-helical-pile-foundations-underpinning-existing-foundations/650270.png","ImageObject",300,407,{"name":42,"@type":43},"Finn","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-10-30","2026-10-24",true,{"@type":52,"interactionType":53,"userInteractionCount":33},"InteractionCounter",{"@type":54},"ViewAction",{"@type":56,"mainEntity":57},"FAQPage",[58,64,68],{"name":59,"@type":60,"acceptedAnswer":61},"What is underpinning and why is it used?","Question",{"text":62,"@type":63},"Underpinning supports an existing foundation using a pier or piling system. It stabilizes foundations when movement is a concern or when new loads must be added.","Answer",{"name":65,"@type":60,"acceptedAnswer":66},"How are helical piles designed and proof tested for underpinning?",{"text":67,"@type":63},"A structural engineer identifies required compression and tension capacity on foundation drawings, and a specialty pile engineer designs and sizes the piles. Alternatively, proof testing verifies capacity by applying load through the bracket, one pile at a time to 100% of required capacity when sufficient dead load is available.",{"name":69,"@type":60,"acceptedAnswer":70},"How is pile installation acceptance determined?",{"text":71,"@type":63},"Installation torque and depth are measured and recorded at 3-foot intervals. Torque-depth acceptance is based on recognized capacity:torque relationships, continuing extension sections until proper final torque is achieved, and refusal conditions are handled per the stated criteria.","https://schema.org",{"og:url":32,"og:type":74,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":76,"canonical":32},"index,follow",{"doc_id":78,"site_id":7},650270,1792823535,{"code":4,"msg":81,"data":82},"success",[83,87,91,95,100,105,110,114,119,122,126],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":84,"show_sort_weight":85,"slug":86},"Story & Novel",90,"story-novel",{"id":26,"doc_module":4,"doc_module_name":25,"category_name":88,"show_sort_weight":89,"slug":90},"Literature",80,"literature",{"id":33,"doc_module":4,"doc_module_name":25,"category_name":92,"show_sort_weight":93,"slug":94},"Exam",70,"exam",{"id":96,"doc_module":4,"doc_module_name":25,"category_name":97,"show_sort_weight":98,"slug":99},5,"Comic",60,"comic",{"id":101,"doc_module":4,"doc_module_name":25,"category_name":102,"show_sort_weight":103,"slug":104},6,"Technology",50,"technology",{"id":106,"doc_module":4,"doc_module_name":25,"category_name":107,"show_sort_weight":108,"slug":109},7,"Healthcare",40,"healthcare",{"id":111,"doc_module":4,"doc_module_name":25,"category_name":29,"show_sort_weight":112,"slug":113},8,30,"research-report",{"id":115,"doc_module":4,"doc_module_name":25,"category_name":116,"show_sort_weight":117,"slug":118},9,"Religion & Spirituality",20,"religion-spirituality",{"id":117,"doc_module":4,"doc_module_name":25,"category_name":120,"show_sort_weight":117,"slug":121},"World Cup","world-cup",{"id":123,"doc_module":4,"doc_module_name":25,"category_name":124,"show_sort_weight":123,"slug":125},10,"Lifestyle","lifestyle",{"id":127,"doc_module":4,"doc_module_name":25,"category_name":128,"show_sort_weight":96,"slug":129},19,"General","general",{"code":4,"msg":81,"data":131},{"doc_id":78,"user_id":132,"nickname":42,"user_avatar":133,"doc_module":4,"category_id":111,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":33,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":33,"language":139,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":12,"update_tm":79,"read_time":123},34359740700684,"https://ap-avatar.wpscdn.com/avatar/1f400023980c374ae676?_k=1777273430885731487","Example Geotechnical Report Recommendations-Underpinning  \nMAGNUM Helical Pile Foundations  \nUnderpinning Existing Foundations  \nUnderpinning is the process of supporting an existing foundation using a foundation pier or piling system. Underpinning is used to stabilize foundations due to concerns over foundation movement or for bolstering an existing foundation so that new loads can be added. A common method of underpinning is to attach helical piles to existing concrete using a steel bracket. Helical piles represent a cost effective underpinning solution. Benefits of helical piles include exceptional uplift resistance, no drill spoil, no concrete delays, low noise, and no vibrations. Helical pile design and construction criteria for underpinning are as follows:  \nHelical Piles  \n1. Helical piles are available in a variety of sizes and configurations depending on loads and type of structure. Helical piles commonly used in underpinning applications typically have a shaft dimension of up to 3.5 inches and allowable capacity generally less than 20 tons. Many \"off the shelf\" brackets and underpinning systems are available in this capacity range. For larger commercial and industrial applications, custom brackets are available but require project specific engineering. Given advantages of redundancy and closer spacing, it is generally more dependable to use a larger number of smaller underpinning piles on projects with heavy loads rather than fewer high capacity underpinning piles.  \n2. Project structural engineer should locate helical piles on foundation drawings and identify required compression and tension capacity. Helical piles should be designed and sized by a specialty pile engineer licensed in the project state. Otherwise, helical piles should be proof tested by applying load to the pile through the bracket. Proof testing verifies capacity of the pile, bracket, and connection to structure. Proof testing should be performed one pile at a time to 100% of required pile capacity provided there is sufficient dead load.  \n3. The number and size of helical bearing elements should be as required to achieve bearing in a base line stratum consisting of [ describe bearing stratum ] with a standard resistance blow count (N70) of [ report average Nvalue ] . A minimum factor of safety of 2.0 is required for bearing and pullout capacity determination.  \n4. As a base line for bid purposes, properly sized helical piles can be expected to achieve bearing at a depth below ground surface of [ depth of stratum or range] plus the aggregate spacing between helical bearing elements. To ensure proper embedment for pullout and to resist effects of frost and shrink/swell  \nMAGNUM ISO Doc. F402 1  \nCopyright ©2015  \nExample Geotechnical Report Recommendations-Underpinning  \nMAGNUM Helical Pile Foundations  \nsoils, we recommend piles have a minimum depth of [ state minimum depth if any ] .  \n5. Helical piles and brackets used for permanent underpinning are typically hotdip galvanizing in accordance with ASTM A153 . Helical piles and brackets used for temporary underpinning can be bare steel.  \n6. Helical piles used for underpinning are generally not relied upon to resist lateral loads. Lateral loads, if any, should be resisted by other means such as separate helical anchors, tie-backs, floor slabs, or other bracing.  \n7. Per IBC, all piles shall be laterally braced. This is especially important for slender underpinning piles. Lateral bracing can be achieved by arranging three or more piles under an isolated column or by staggering piles on each side of long walls or grade beams. Exceptions are light residential construction, wherein lateral bracing often can be achieved by internal strength of stem walls and floor systems.  \n8. Tolerance for helical pile placement is typically +/-2 inch horizontal, +/-1/8 inch elevation, and 3 deg orientation/inclination. Helical piles installed out of tolerance often can be removed and repositioned.  \n9. Installation to","cbCaimGHq8c5lcA3","https://ap.wps.com/l/cbCaimGHq8c5lcA3","pdf",196126,"English","# Underpinning and Helical Pile Foundations\n## Purpose and Benefits\n## Helical Pile Design and Construction Criteria\n## Installation, Bracing, and Acceptance","[{\"question\":\"What is underpinning and why is it used?\",\"answer\":\"Underpinning supports an existing foundation using a pier or piling system. It stabilizes foundations when movement is a concern or when new loads must be added.\"},{\"question\":\"How are helical piles designed and proof tested for underpinning?\",\"answer\":\"A structural engineer identifies required compression and tension capacity on foundation drawings, and a specialty pile engineer designs and sizes the piles. Alternatively, proof testing verifies capacity by applying load through the bracket, one pile at a time to 100% of required capacity when sufficient dead load is available.\"},{\"question\":\"How is pile installation acceptance determined?\",\"answer\":\"Installation torque and depth are measured and recorded at 3-foot intervals. Torque-depth acceptance is based on recognized capacity:torque relationships, continuing extension sections until proper final torque is achieved, and refusal conditions are handled per the stated criteria.\"}]","Example Geotechnical Report Recommendations-Underpinning - MAGNUM Helical Pile Foundations - Underpinning Existing Foundations | PDF"]