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A few days later, Edgar A. Bayley was recalled to the witness stand to answer more
questions on uplift relief. He was asked “What do you think about the practice of under-draining
all of the dam, not just the bottom, but the side portions, as well, to prevent erosion, supposing a
leak starts in the upstream face, if there was a series of drainage pipes in there to pick up that
seepage and carry it to the canyon below, without erosion, would that not be a measure for
safety?” He responded “I would consider that good practice as a measure of safety.”
Bayley stated that he had not designed the St. Francis Dam, only Hollywood
[Mulholland] Dam. When asked how he had accommodated the relief of “upthrust” into the
design, he replied: “there are several ways to take care of upthrust. One is by a gallery along
the upper toe and another by a system of drain pipes and another by blocks of concrete to let the
upthrust come where it will. In the Hollywood dam we took care of it by a system of drain pipes,
and when I left there, there were many drain pipes installed.” Bayley was likely referring to well
casings installed in the exploratory borings beneath the main dam, connected to some sort of
outlet pipe, similar to what was installed at St. Francis Dam.
Bayley cited the two principal references he used in the design of Hollywood Dam as
being Morison & Brodie (1916) and Wegmann (1922). The answers provided by Hurlbut,
Bayley, Hemborg, and Phillips suggest that BWWS never attempted to provide internal drainage
within Hollywood or St. Francis Dams, nor did they provide uplift relief under the sloping
abutments. Internal drains had been included in the Olive Bridge cyclopean masonry gravity dam
in New York, but that was one of the only masonry dams so fitted prior to the mid-1920s.

GROUTING OF TRANSVERSE SHRINKAGE CRACKS

BWWS Office Engineer Edgar A. Bayley was then queried about the absence of expansion
[contraction] joints in St. Francis Dam. Bayley stated that “many engineers place these at 50 foot
intervals, but Mr. Mulholland does not – he just grouts the shrinkage cracks after they occur.”
He then conceded that “the prevalent practice in current times has been towards employing
expansion joints,” and mentions other mass concrete dams then under construction, including:
Exchequer, Don Pedro, Lancha Plana (Pardee), San Gabriel at the Forks, and Pacoima Dams. All
of these projects were employing contraction joints. The Forks Dam was then under construction
in San Gabriel Canyon, and was slated to be 29 times the volume of St. Francis Dam.
William Mulholland chose to forego the insertion of regular contraction joints, which
would have required additional formwork and insertion of waterstops. When asked why BWWS
did not employ water stops, Bayley replied these were not used “because they are patented.” The
alternative practice was to grout or caulk shrinkage cracks after they developed. The Governor’s
Commission opined that many existing concrete masonry dams had been built prior to 1928
without using contraction joints (Committee Report, 1928, p.15).
During the testimony of Edgar Bayley he laid the responsibility for handling shrinkage,
stresses, keys, and post-construction grouting of Hollywood and St. Francis Dams on William
Mulholland, the Chief Engineer. He asserted that Mr. Mulholland and other designers ”have
done so without employing regular contraction (shrinkage) joints, which are grouted after the
concrete has cured some amount.

Significant shrinkage cracks developed in the St. Francis Dam as the mass concrete cured
(BWWS employed a 4-sacks of cement per cubic yard mixture, the same as the US Bureau of
Reclamation). BWWS Chief Surveyor James E. Phillips testified that “the first prominent
shrinkage crack was about 75 to 100 feet east of the right abutment thrust block.” Another crack

World Environmental and Water Resources Congress 2017