{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,11]],"date-time":"2025-09-11T20:10:21Z","timestamp":1757621421385,"version":"3.44.0"},"reference-count":32,"publisher":"ASTM International","issue":"3","content-domain":{"domain":["asmedigitalcollection.asme.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2018,5,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>Micropiles, which are small-diameter deep foundation solutions with diameters that can measure up to 300\u00a0mm, are often used to reinforce new and existing foundations. Their use in the foundations of structures with high eccentricity, such as wind towers when subjected to wind loads, may lead to more efficient and economical solutions. As the new generation of wind towers will reach more than 150\u00a0m tall, very large and uneconomical gravity foundations are required. In regions of high seismicity this problem is aggravated. To evaluate the behavior of micropiles under variable loading and predict the improvement of the reinforced solution, load tests were performed on steel micropiles under controlled laboratory conditions. A total of 36 tests were conducted on 3-m-long pipe micropiles, both while isolated and in 2 by 2 groups, with three different spacings. The micropiles were installed in a cylindrical container filled with calibrated sand and tested under monotonic and cyclic loading, first without grout, then when low-pressure grouted and retested, with the aim to evaluate the improvement caused by the grout injection, the micropile spacing, and application of cyclic loading both in terms of resistance and stiffness. An improvement both in stiffness and resistance due to the grouting was obtained and, for the applied cyclic loading, there was no clear reduction in micropile cyclic stiffness. The presented results provide a tool for the calibration of numerical models to estimate the behavior of real-scale micropiles installed in higher density sand.<\/jats:p>","DOI":"10.1520\/gtj20160284","type":"journal-article","created":{"date-parts":[[2018,3,20]],"date-time":"2018-03-20T01:05:48Z","timestamp":1521507948000},"page":"526-542","update-policy":"https:\/\/doi.org\/10.1115\/crossmarkpolicy-asme","source":"Crossref","is-referenced-by-count":10,"title":["Axial Monotonic and Cyclic Testing of Micropiles in Loose Sand"],"prefix":"10.1520","volume":"41","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9822-8692","authenticated-orcid":false,"given":"R.","family":"Matos","sequence":"first","affiliation":[{"name":"Civil Engineering Department, University of Coimbra 1 , Rua Lu\u00eds Reis Santos, P\u00f3lo II, 3030-788 Coimbra ,","place":["Portugal"]}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6424-8561","authenticated-orcid":false,"given":"P.","family":"Pinto","sequence":"additional","affiliation":[{"name":"Civil Engineering Department, University of Coimbra 2 , Rua Lu\u00eds Reis Santos, P\u00f3lo II, 3030-788 Coimbra ,","place":["Portugal"]}]},{"given":"C.","family":"Rebelo","sequence":"additional","affiliation":[{"name":"Civil Engineering Department, University of Coimbra 2 , Rua Lu\u00eds Reis Santos, P\u00f3lo II, 3030-788 Coimbra ,","place":["Portugal"]}]},{"given":"M.","family":"Veljkovic","sequence":"additional","affiliation":[{"name":"Delft University of Technology, Faculty of Civil Engineering and Geosciences 3 , Building 23, Stevinweg 1, 2628 CN Delft, PO Box 5048, 2600 GA Delft ,","place":["The Netherlands"]}]},{"given":"L.","family":"Sim\u00f5es da Silva","sequence":"additional","affiliation":[{"name":"Civil Engineering Department, University of Coimbra 2 , Rua Lu\u00eds Reis Santos, P\u00f3lo II, 3030-788 Coimbra ,","place":["Portugal"]}]}],"member":"381","published-online":{"date-parts":[[2018,3,22]]},"reference":[{"issue":"12","key":"2025090809224354000_B1","doi-asserted-by":"publisher","first-page":"2017","DOI":"10.1139\/cgj-2014-0448","article-title":"The Performance of Micropiled Raft in Clay Subjected to Vertical Concentrated Load: Centrifuge Modeling","volume":"52","year":"2015","journal-title":"Can. 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