Concrete dowel placement method and apparatus

Abstract

A concrete surface with a cold joint, dowel slip system and method for forming that surface are provided. Baseplates having tubular projections are fastened to at least one first form using fasteners extending part way into the first form, with the first form forming part of a periphery of a first concrete slab. When the first form is removed, the baseplates, projections and fasteners remain embedded in the first concrete slab. Slip dowels are inserted into the tubular projections and a second concrete is poured adjoining the first concrete slab, with the second concrete embedding the slip dowels, backplates and projecting distal ends of the fasteners and forming a cold joint.

What is claimed is: 
     
         1 . A concrete dowel placement system comprising:
 a finished 2×4 or 4×6 stud having a stud length with opposing first and second side walls and opposing top and bottom edge walls;   a plurality of baseplates each having opposing front and back sides with a thickness of between 0.1 and 0.25 inches and made of a polymer which does not split or crack when a fastener is forced through the baseplate, each baseplate having an outer periphery which is located between the top and bottom edge walls of the stud and 0.5 inches or more from the top edge wall of the stud;   multiple fasteners forced through each of different ones of the baseplates fasten the baseplate to the first side wall of the stud so the planar periphery cooperates with the first side wall of the stud to which the baseplate is fastened to form a seal that inhibits the entry of poured concrete between the baseplate and stud, each fastener has a fastener length which extends into the stud a distance of at least ¼ inch and no more than 1 inch;   a separate tubular projection extending from each respective baseplate along a longitudinal axis that is substantially perpendicular to the front face of the baseplate from which the projection extends, each tubular projection having a length of 4 to 9 inches with a closed distal end and having a hollow interior configured to receive a cylindrical shaft 0.2 to 0.4 inches in diameter.   
     
     
         2 . The system of  claim 1 , wherein the fasteners extend a distance of 0.3 to 0.5 inches into the stud and comprise nails or staples or both, and wherein the hollow interior is configured to receive a shaft 0.2 to 0.3 inches in diameter. 
     
     
         3 . The system of  claim 2 , wherein the tubular projections have engagement features to better entrain the tubular projections in the concrete, and wherein the tubular projections are spaced at 18 inch intervals along the stud length. 
     
     
         4 . The system of  claim 2 , wherein there are only three staples holding each of the baseplates to the stud. 
     
     
         5 . A concrete surface having first and second concrete slabs joined by a cold joint, comprising:
 a plurality of polymer baseplates embedded in the first concrete surface at intervals along the cold joint, each baseplate having an outer periphery located at least 0.5 inches from a top surface of the first slab of concrete at the cold joint, each baseplate having a tubular projection extending perpendicular from the baseplate and into the first concrete slab, each tubular projection having a length of 4 to 9 inches, each baseplate having at least three fasteners extending from the first concrete surface, through the baseplate and into the second concrete surface a distance of 0.2 to 1 inch with a head of each fastener embedded in the first concrete slab and distal ends of a further plurality of these fasteners embedded in the second concrete slab;   a plurality of straight, stainless steel or fiberglass slip dowels having first and second opposing ends and a length of 4 to 18 inches, the second end of each slip dowel being embedded in the second concrete slab and the first end extending into a different one of the tubular projections, each slip dowel having a diameter of 0.2 to 0.4 inches.   
     
     
         6 . The concrete surface of  claim 5 , wherein the slip dowels are made of stainless steel and have a diameter of 0.2 to 0.3 inches. 
     
     
         7 . The concrete surface of  claim 5 , wherein the slip dowels are made of fiberglass and have a diameter of 0.2 to 0.3 inches. 
     
     
         8 . The concrete surface of  claim 5 , wherein each of the slip dowels has a shear strength of 6000 psi. 
     
     
         9 . The concrete surface of  claim 5 , wherein the slip dowels are made of stainless steel and have a diameter of 0.2 to 0.3 inches, and wherein the fasteners extend the through the baseplate and into the second concrete surface a distance of 0.25 to 0.6 inches. 
     
     
         10 . A method of forming a cold joint between adjoining sequentially formed first and second slabs of concrete, comprising:
 (a) arranging at least one stud to form at least a portion of a periphery of the first slab of concrete;   (b) fastening a plurality of baseplates to the at least one stud with a plurality of at least three separate fasteners forced through each respective baseplate and into the stud to which the baseplate is fastened, each baseplate having opposing front and back sides with a thickness of between 0.015 and 0.25 inches, each baseplate made of a polymer which does not split or crack when each fastener is forced through the baseplate and into the stud, each baseplate having an outer periphery which is located between a top and bottom edge wall of the stud and 0.5 inches or more from a top edge wall of the at least one stud, each fastener having a fastener length which extends into the stud a distance of at least ¼ inch and less than 1 inch, each baseplate having a tubular projection extending along a longitudinal axis that is substantially perpendicular to the front face of the baseplate from which the projection extends, each tubular projection having a closed distal end and having a hollow interior configured to receive a straight cylindrical shaft 0.2 to 0.4 inches in diameter through an opening in the baseplate, each tubular projection having a length of 4 to 9 inches from the baseplate and having a sidewall thickness less than 0.1 inches;   (c) pouring a first concrete into an area bounded in part by the at least one stud to entrain the plurality of baseplates and tubular projections;   (d) leveling and finishing the first concrete to form the first concrete slab upon hardening of the first concrete, with the tubular projections extending into the first concrete slab; and   (e) removing the at least one stud, leaving the baseplates embedded in the first concrete slab along a first edge of the first concrete slab with distal ends of the fasteners extending from the respective baseplates along that first edge of the first concrete slab.   
     
     
         11 . The method of  claim 10 , further comprising:
 inserting a slip dowel into each tubular projection through the hole in the baseplate, each slip dowel having a diameter of 0.2 to 0.4 inches and made of stainless steel or fiberglass and having a length of 12-18 inches, each tubular projection configured to slidingly but tightly receive the slip dowel;   pouring a second concrete to entrain the slip dowels and the distal ends of plurality fasteners; and   leveling and finishing the second concrete to form the second concrete slab upon hardening of the second concrete.   
     
     
         12 . The method of  claim 10 , wherein the slip dowels are made of stainless steel and have a diameter of 0.2 to 0.3 inches. 
     
     
         13 . The method of  claim 10 , wherein the slip dowels are made of fiberglass and have a diameter of 0.2 to 0.3 inches. 
     
     
         14 . The method of  claim 10 , wherein there are only three fasteners holding each baseplate to the at least one stud. 
     
     
         15 . The method of  claim 10 , wherein the fasteners have a length of 0.2 to 0.5 inches extending into the stud. 
     
     
         16 . The method of  claim 11 , wherein the slip dowels are made of stainless steel and have a diameter of 0.2 to 0.3 inches. 
     
     
         17 . The method of  claim 11 , wherein the slip dowels are made of fiberglass and have a diameter of 0.2 to 0.3 inches. 
     
     
         18 . The method of  claim 11 , wherein there are only three fasteners holding each baseplate to the at least one stud. 
     
     
         19 . The method of  claim 11 , wherein the distal ends of the fasteners have a length of 0.2 to 0.5 inches extending into the second concrete slab. 
     
     
         20 . The method of  claim 11 , wherein the fasteners are nails or staples.