Design Guide for Pile Caps by Timothy Mays

Appendix C
Pile-to-Pile
Cap Connections

C-i



Design Guide for Pile Caps—Appendix C

APPENDIX C Cast-in Place
Pile-to-Pile Cap Connections Concrete Cap

C.1 General 6 in. 6 in. 4 in. 4 in.

In Appendix C, an overview of pile-to-pile cap connections is Embedded Embedded Embedded Embedded
presented. Per ACI 318-14 Section 1.4.6, ACI 318-14 does not Pipe Pile H-Pile Prestressed Timber Pile
govern the design of these connections except for a limited
number of provisions for prestressed concrete piles used in Pile
structures located in Seismic Design Categories D, E, and F.
Special pile and pile cap provisions applicable to these high Fig. C.1 Typical pinned pile-to-pile cap connection detail. Mechanical tie
seismic design categories are summarized separately in Chap- detail not required unless pile tension is a design consideration.
ter 7 of this design guide. All provisions applicable to pile-to-
pile cap connections are included in Chapter 18 of the 2012 Extend some Dowels Cast-in Place
IBC. In general, the 2012 IBC permits the designer to model of the strand Concrete Cap
the pile head using whatever fixity the designer deems ap- and anchor
propriate and justified by the detailing present at the interface.
Pin headed piles and fixed headed piles are commonly used 1.5D
but pile heads with partial fixity are detailed on occasion.
D
This guide focuses on two pile head connection types. Pinned
head connections are the common pile head connection detail Fully Extended Doweled
assumed in all previous chapters of this guide and are made
using simple pile embedment with or without longitudinal Embedded Strand (Prestressed)
dowels extending from the pile into the pile cap depend-
ing on whether or not pile tension is a design consideration. Pile (All) (Prestressed)
Although fixed pile heads are not considered in this design
guide, they are commonly used when additional pile strength Fig. C.2 Some commonly used fixed pile-to-pile cap connection details.
or stiffness is desired and a brief overview of connection
details and load path issues is justified.

C.2 Pinned Head Pile-to-Pile Cap
Connections

The design procedures presented in Chapters 5 and 6 of this
design guide and the tabulated designs in Section T have been
developed assuming pinned connections exist at the pile-to-
pile cap interface. The common pinned head connection detail
is made using minimum pile embedment. 2012 IBC Section
1810.3.11 requires all piles to be embedded a minimum of
3 inches into the pile-cap and further requires a clear edge
distance from the pile surface to the edge of the pile cap of at
least 4 inches. These minimum dimensions are exceeded by
the recommendations presented earlier in this design guide.
Fig. C.1 presents typical pinned head connection details for
prestressed, steel and timber piling. Note that when tension
is a design consideration, a mechanical device must tie the
pile directly to the pile cap.

C.3 Fixed Head Pile-to-Pile Cap
Connections

There are many options available to the designer opting to
model the pile head as fixed to the pile cap. Some common
details are shown in Fig. C.2. The minimum prescriptive
dimensions presented in 2012 IBC Section 1810.3.11 (3 inches
embedment into the pile-cap and 4 in. clear edge distance)
as discussed in the previous section still apply. The example
fully embedded pile shown in Fig. C.2 may require 1.0D to
2.0D embedment into the pile cap to develop the full moment
capacity of the pile. See ASCE/COPRI 61-14 Seismic Design of
Piers and Wharfs (2014) for design procedures associated with
various fixed head pile configurations.

Concrete Reinforcing Steel Institute C-1

Design Guide for Pile Caps

Notes

Concrete Reinforcing Steel Institute



Description of Manual

This design guide has been developed to provide the practicing
engineer with a detailed overview of pile cap design, detailing, and
analysis methodologies that represent the current state of practice
in the industry.The guide contains comprehensive technical content
and practical design examples utilizing approximately 30 different,
yet commonly used, pile cap configurations.Tabulated designs are
also provided for all aforementioned pile cap configurations and
a wide range of vertical loading, lateral loading, and overturning
effects. In order to better understand the behavior of deep pile
caps, a finite element study was performed and recommendations
obtained from that study are presented here.

Concrete Reinforcing 10-DG-PILE-CAPS-2015-3.5m
Steel Institute

[ [ [933 North Plum Grove Road Schaumburg, IL 60173 Tel. 847.517.1200 www.crsi.org