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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
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      <title>PILE DRIVING: HAMMERS AND DRIVING METHODS</title>
      <link>https://trid.trb.org/View/109971</link>
      <description><![CDATA[THIS PAPER IS PRIMARILY CONCERNED WITH THE MOST COMMON TYPES OF PILE HAMMERS IN EXISTENCE TODAY, BUT SOME ATTENTION IS GIVEN TO THOSE SPECIAL SYSTEMS THAT HAVE SEEN LIMITED USE DURING THE PASE DECADE AND MAY BE THE NUCLEI OF THE DRIVING SYSTEMS OF THE FUTURE. THE HEART OF ANY PILE-DRIVING SYSTEM IS THE PILE HAMMER. MODERN CONTRACTORS USE IMPACT TYPES RANGING FROM THE "ANCIENT" DROP HAMMER, THROUGH SINGLE-AND DOUBLE-ACTING HAMMERS, TO DIFFERENTIAL HAMMERS. STEAM AND AIR ARE STILL THE BASIC SOURCES OF POWER FOR HAMMERS, BUT LATELY DIESEL HAMMERS AND HIGH-PRESSURE HYDRAULICS HAVE GAINED ACCEPTANCE. BECAUSE A CONSTANT ENERGY SOURCE IS SERIOUSLY AFFECTED BY PILE CUSHIONS OF VARYING CHARACTERISTICS, "PERMANENT" CAP BLOCKS ARE NOW IN WIDESPREAD USE. LOW-FREQUENCY VIBRATORS ARE USED PRIMARILY FOR DRIVING NONBEARING PILES AND FOR EXTRACTING SHEET PILES. HIGH-FREQUENCY (RESONANT) VIBRATORS, THOUGH CURRENTLY EXPENSIVE TO PURCHASE AND OPERATE, HAVE MUCH WIDER FIELDS OF APPLICATION INCLUDING THE DRIVING OF DISPLACEMENT BEARING PILES. PILE-DRIVING SYSTEMS OF THE FUTURE WILL INCLUDE LARGER HAMMERS (250,00 FT-LB OR MORE) WITH SELF-CONTAINED POWER SOURCES, BOTH DIESEL AND STEAM, AND SIMPLE, LESS EXPENSIVE BUT MORE RELIABLE HIGH-FREQUENCY, HIGH-POWER VIBRATORS. /AUTHOR/]]></description>
      <pubDate>Wed, 26 May 1971 00:00:00 GMT</pubDate>
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