National Council of State Boards of Engineering Examiners (1932)
In October 1932 a National Council of State Boards of Engineering Examiners (NCSBEE) was endorsed at a meeting in New York of the National Bureau of Engineering Registration (NBER), headquartered in Columbia, South Carolina. NCSBEE sought to create standardized civil engineering registration examinations and requirements so reciprocity of licenses between the 28 states mandating professional registration could be undertaken more efficiently. NCSBEE changed its name to the National Council of Engineering Examiners (NCEE) in 1967. NCEE developed standardized tests which were gradually adopted by most states, beginning in the 1960s. NCEE broadened its scope to include establishment of a Model Rule for Professional Conduct in 1979, which many courts have considered as national standards for professional engineering conduct. In 1989 NCEE became the National Council of Examiners for Engineering & Surveying (NCEES). Its headquarters remains in South Carolina (at Clemson).
California remained unaligned with the national examination concept until 1975, when they acquiesced to the standardized NCEE examination, which they have since employed. The reason the California board gave for this reticence was the “eastern bias” they perceived in the NCSBEE/NCEE exams, which had less emphasis on transportation engineering problems, as compared to California’s own tests.
Landslides shut down Pacific Coast Highway (1932)
As more and more roads were built into hillside areas in the burgeoning 1920s, “storm damage” via flooding and cut slope failures became commonplace around southern California. Despite the many problems encountered along the Pacific Palisades, the “Roosevelt Highway” was pushed along the coast from Santa Monica to Point Mugu in 1928-29. This highway opened up much of the coastal area to development, and soon suffered problems.
One of the more innovative measures taken at this time was in response to a series of bluff failures below the McCormick Estate, on Corona del Mar and Alma Real, just above the old Roosevelt Highway (later renamed, see below). The block glide landslide that shut down the highway in November 1932 was the Quelinda Estate Landslide. It soon developed into one of the earliest geologic appraisals of landslippage in southern California. Consulting geologist Harry R. Johnson used aerial photo overlays to illustrate the geologic conditions along 1-/34 miles of coastline, the first time this technique was employed. He discovered that the slide was moving on a weak clay stratum about 10 feet above the base of the bluffs. Civil engineer Robert A. Hill of Quentin, Code, and Hill Consulting Engineers of Los Angeles attacked the clay seam at the base of the cliffs, employing a novel system of hand-excavated tunnels to circulate hot air to desiccate the clay. Adits were tunneled into this stratum to drain the layer, but no free water was encountered. A gas-powered furnace was installed at the base of the cliffs connected to a series of blowers to desiccate the clay, and, thereby, increase its shear strength. (see R.A. Hill, 1934, Clay stratum dried out to prevent landslips: Civil Engineering, v. 4, p. 403-07). The heaters were run between 1933-39 and it was estimated that 3,000 lbs of water per day was thereby evaporated from the clay stratum .
In 1940-41 the Roosevelt Highway was widened to improve traffic safety and speeds, and was re-christened Pacific Coast Highway (PCH). This widening and realignment was carried out using mass grading. Storms during the winter of 1939-40 had caused several landslides that closed PCH, precipitating the first of many generations of remedial grading measures to battle regression of these cliffs (see D.H. Greeley, 1940, Prevention of Slides as a Safety Factor: Calif. Hwys & Public Works, v.19:5 [May], p. 13-14).
The Riley and Field Acts (1933)
Two significant pieces of legislation came out of the March 10, 1933 Magnitude 6.3 Long Beach earthquake. On April 25, 1933 the State legislature passed the Field Act, named after Sacramento Assemblyman Charles Field, the key sponsor of the legislation. His bill focused on making public school buildings in California more earthquake resistant (all K-12 and community college school buildings). It was also the first statewide legislation that mandated earthquake resistant construction in the United States. The quake destroyed or rendered unsafe 230 school buildings in Southern California because these were constructed of unreinforced masonry. Fortunately, the quake occurred at 5:55 PM on a Friday, after most everyone had gone home, and thousands of children’s lives were thereby spared.
The Field Act was introduced with the Riley Act, which together, all but banned unreinforced masonry construction, requiring that earthquake forces be included in the design of new structure, and all existing public schools. This included a requirement for base shear calculations, and that school buildings must be able to withstand lateral forces equal to at least 3% of the building total mass. The Act also established the Office of the State Architect (now Division of the State Architect or DSA) which developed design standards, quality control procedures, and required that schools be designed by registered architects and engineers. These professionals are required to submit their plans to the State Architect for review and approval prior to construction. The same professionals were also required by the Act to periodically inspect the construction while underway and verify that the actual work completed is in compliance with the approved drawings. Peer review was also introduced as another quality control procedure.
The other significant legislation that came out of the Long Beach earthquake was the Riley Act (named after Assemblyman Harry B. Riley of Long Beach), approved by the State legislature on May 27, 1933. The act required all cities and counties in California to establish departments to regulate building construction. Roughly 10 to 15 percent of California’s present structures were built prior to 1933, when few cities had building codes (the Uniform Building Code was introduced in 1927, but was only adopted by a few of the larger municipalities, such as Los Angeles). The Riley Act required local jurisdictions to establish building and safety departments and inspect new construction, mandating that all structures in the state be designed to withstand a horizontal acceleration of 0.02g. These requirements applied only to new, non-agricultural structures. California building officials could add to the Riley Act requirements at their own discretion (such as Los Angeles, Long Beach, Santa Barbara, San Francisco, and Palo Alto). The Riley Act exerted an enormous impact on California because structures built since 1933 have been constructed with some minimal measure of lateral reinforcement and load transfer elements within the framing, and later, between the framing and the foundations.
Since the 1960s, California codes have become more uniform across local jurisdictions (see discussion of the Uniform Building Code, in 1927 and 1933). The Riley Act includes exemptions for wood frame structures of two stories or less, as well as biplexes and single-family residences of all construction in unincorporated areas (only one person was killed inside a single-story wood frame dwelling by any California earthquake during the 20th Century). However, many counties enhance their requirements for such buildings beyond these statewide minimums.
Adoption of seismic loads in the Uniform Building Code (1933)
Following the March 1933 Long Beach Earthquake, the State of California required every municipality to adopt a building code (under the Riley Act, described above). 114 California municipalities adopted the 1933 Edition of the UBC, including most of the larger cities in southern California. Prior to 1933 only Palo Alto and Santa Barbara had adopted codes that required lateral forces seismic events. Due to the poor performance of unreinforced masonry structures during the Long Beach earthquake, the 1933 UBC required all school of two stories or more in height to be built of reinforced concrete or structural steel frame construction. Single story schools were required to have fire-resistant walls and floors, and fire-retarding roofs. All public buildings, including schools, were required to provide for lateral forces from earthquake motion, and the use of lime mortar was altogether outlawed.
School districts and local municipalities complained, but a vigorous program of retrofit and school reconstruction, as well as new construction, soon ensued, providing work for architects, structural engineers, and contactors. It also bolstered the prestige and respect of licensed structural engineers, and their organizations, such as SEAOSC and SEAOCC. Los Angeles adopted a restrictive version of this code in 1943 (described below), which included minimum pseudo static load requirements for seismic detailing, as well as more fire resistant construction details.
Proctor Compaction Test (1933)
Ralph R. Proctor, PE (1894-1962) was a field engineer for the Los Angeles Department of Water & Power (LADWP) on the Bouquet Canyon Dams in 1932-34. Construction Superintendent H. L. Jacques asked Proctor to devise a method of testing the compacted fill so the LADWP could demonstrate to the world that they were constructing the safest dam possible, in the wake of the March 1928 failure of the St. Francis Dam, built by DWP (which Jacques also supervised and which Proctor served as the resident field engineer). Proctor’s test procedure measures the maximum wet density, and controls the compactive effort based on the total weight, not the volume, of the test sample. The primary advantage of Proctor’s method is that the test results could be computed onsite, as evaporation of the compacted sample not being necessary. This allowed immediate adjustment of the soil water content, which was the critical variable the contractor needed to know.
Proctor developed a “dynamic compaction test,” using an impact hammer, combined with a cylindrical mold, similar to that proposed by O.J. Porter for his California Bearing Ratio test in 1929. Proctor’s procedure employed a smaller cylindrical mold, just four inches in diameter and 4.6 inches high, with a removable mold collar, giving it a volume of 1/30th cubic foot. A 5.5 pound hammer, 2 inches in diameter, was pulled upward and allowed to free-fall 12 inches, onto the soil (5.5 ft-lbs per blow), simulating the dynamic impact of sheepsfoot rollers or heavy wheel loads on the soil. The soil specimen was compacted in three lifts, with an average thickness of 1.33 inches/lift. 25 blows were exerted per lift, which exerted 137.5 ft-lbs/lift. The total input energy for the three lifts was 3 x 137.5 = 412.50 ft-lbs on a soil sample with a volume of 1/30th cubic foot. This equals 12,400 ft-lbs of dynamic compactive energy per cubic foot of soil.
Proctor published his recommended procedure in a series of four articles that appeared in Engineering News Record on August 31st, September 7th, September 21st, and September 28th, 1933. The test soon became a nation-wide standard, because of its simplicity, low cost, and utility in providing near real-time fill control. It was eventually designated as BurRec Test E11 (adopted in 1947), ASTM Test D698 (adopted July 1950), and AASHTO T99 (also adopted in1950).
First Sand Cone Field Density Tests (1933)
During construction of the San Gabriel Dam by the Los Angeles County Flood Control District in 1933-37, engineer Paul Baumann, assisted by Ralph R. Proctor and N. M. Imbertson, supervised a series of field tests to evaluate the best means of compacting earth and disaggregated rocky fill materials with 25-ton sheepsfoot rollers and rolling tampers, including an extensive evaluation of sluicing using large quantities of water (two cubic yards of water per cubic yard of rock placed). These test revealed the value of hydrocompaction and arching during mechanical compaction. During the field tests they settled on using 12-inch diameter test holes filled with “dry beach sand” and concluded that the dry in-place bulk density should be the governing factor determining the intrinsic properties of the fill (described in P. Baumann, Design and Construction of San Gabriel Dam No. 1. ASCE Proceedings 67:7, Sept 1941; and in the Discussions of 1942 ASCE Transactions 107:1644-46).
U.S. Soil Conservation Service established (1933-35)
In June 1933 Congress passed the National Industrial Recovery Act, which included appropriations to combat agricultural soil erosion. This action was prompted by ‘The Dust Bowl’ conditions brought on by extended drought conditions in the Southwestern and Midwestern states. In September 1933 the federal Soil Erosion Service (SES) was established within the Department of Interior with Hugh H. Bennett as its Chief. Bennett had formerly served as a surveyor with the old U.S. Bureau of Soils. The SES established demonstration projects in critically eroded areas across the country to publicize the benefits of soil conservation.
In April 1935 Congress passed Public Law 74-46, which established the Soil Conservation Service (SCS) as a permanent agency within the U.S. Department of Agriculture, again under the direction of Bennett. In 1929 Bennett wrote a book titled “Soil Erosion: A National Menace,” which influenced the decision to establish federal soil erosion experiment stations in 1929.
Bennett instituted a seven-fold increase in demonstration projects for local farmers and SCS began publishing County-wide report “separates,” which included color overlays on then-existing USGS 15-minute (1:62,500 scale) topographic map mosaics. One example would be: E.J. Carpenter and S.W. Cosby, 1939, Soil Survey, Contra Costa County, California: USDA Bureau of Chemistry and Soils, Series 1933, No. 26. A check of this original map not only reveals the soil assignments, but in most instances, also provides an assessment of the undeveloped topography. These were usually prepared by local soil scientists attached to the SCS or in cooperation with the U.C. Agricultural Experiment Stations.
In the late 1930s SCS set about developing more reliable and scientifically-based maps of soil deposits with extensive compendiums of soils properties. In 1920 Professor Curtis F. Marbut of the University of Missouri began developing an agricultural soils classification scheme. In 1927 he translated Glinka's The Great Soil Groups of the World and their Development from German. His classification scheme was unveiled in the 1938 Yearbook of Agriculture, Soils and Men: the 1938 USDA soil taxonomy. He divided soils into pedocals (carbonate rich soils in the drier climates) and pedalfers (soils developed in more humid climes and rich in aluminum and iron. Alfer became the root term for Alfisols. This new scheme met with mixed success.
The decade following the Second World War saw Congress increased appropriations for soil conservation programs. Between 1945-48 a new classification system was developed, culminating with the “7th approximation,“ introduced in 1960, which became the national standard in 1965. This was tweaked slightly to include 10 distinct soil orders in 1975, and expanded to include 12 soil orders in 1999. These details are included here to make the reader aware that soil surveys performed in different decades use differing descriptive terms. In 1994 the name of the agency was changed to the Natural Resources and Conservation Service (NRCS).
National Society of Professional Engineers (1934)
The National Society of Professional Engineers (NSPE) was founded in New York City in 1934 as the national society of engineering professionals from all disciplines, which promotes the ethical and competent practice of engineering, professional licensure, and enhances the image and well-being of the professional of engineering. NSPE established the celebration of National Engineers Week in 1951, in conjunction with President George Washington's birthday (February 22nd). President Washington is considered as the nation's first engineer, notably for his survey work. NSPE has worked with ASCE to establish uniform standards for professional engineering of civil engineers in all 50 states and territories of the United States, which went into effect in 2003. NSPE now serves more than 54,000 members and the public through 53 state and territorial societies and more than 500 chapters.
First course in soil mechanics taught in California (1934)
In 1930 Professor Frederick J. Converse at Caltech in Pasadena began a professional association with Robert V. Lebarre (1871-1944), who had worked for The Foundation Engineering Co. of New York. Lebarre cultivated an interest in the enraging specialty of soils mechanics and foundation engineering. He began doing part-time engineering design work for Lebarre. In 1933 Converse was promoted to assistant professor and established a consulting partnership with R V. LaBarre. In April 1933 Converse published his first article on soil mechanics titled “Distribution of Pressure Under a Footing,” which appeared in Civil Engineering magazine (published by ASCE). It describes a plunger style pressure cell developed by Converse for ascertaining the pressure exerted beneath foundation footings. He began teaching soil mechanics as a graduate course at Caltech in the spring semester of 1934 using the text “A Practical Method for the Selection of Foundations Based on Fundamental Research in Soil Mechanics,” by Professor William S. Housel at the University of Michigan (University of Michigan Engineering research Bulletin No. 13, Oct., 1929). Two of the graduate students in that first soil mechanics class were Trent R. Dames (1911-2000) (BSCE ’33; MS ’34 Caltech) and William W. Moore (1912-2002) (BSCE ’33; MS ’34 Caltech), who went onto establish the firm Dames & Moore in August 1938, after working for R.V. Lebarre.
Downhole Logging of Large Diameter Borings (1935 – onward)
Around 1935 consulting foundation engineer R. V. Lebarre, PE, SE (1871-1944) of Glendale began excavating vertical shafts between two and three feet in diameter with a mobile power auger (described in “Test Pit Exploration Kit for Foundation Study” in the August 6, 1936 issue of Engineering News Record). These borings were of sufficient size and depth (60 to 70 ft deep) to allow a geologist to descend the unshored holes for purposes of evaluating the geologic conditions and making measurements and taking soil or rock samples. These men also used soil penetrometers to record soil stiffness with depth, creating detailed subsurface logs.
The art of downhole logging was lost when Lebarre died in 1944, but was revived in the early 1960s by F. Beach Leighton, PhD, CEG and Robert Stone, PhD, CEG who used these same techniques, but with flexible Boatswain’s Mate rope ladders, which Leighton had used in the late 1940s to descend into glacier crevasses in Alaska. Two excellent articles describing the use of using bucket augers have been published: C.M. Scullin, 1994, “Subsurface exploration using bucket auger borings and down-hole geologic inspection,” AEG Bulletin v. 31:91-105; and P.L. Johnson and W.F. Cole, 2001, “The use of large-diameter boreholes and downhole logging methods in landslide investigations,” Engineering Geology Practice in Northern California, CDMG Bulletin 21-/AEG Spec Pub 12, pp. 95-106. No one has ever been killed while performing downhole logging, although Frank Dennison, CEG lost one of his legs after passing out from gas inhalation and being dragged unconscious out of the borehole.
Establishment of the Soil Mechanics & Foundations Division of ASCE (1936)
At the annual ASCE meeting in July 1936 the society’s Board approved the formation of a new Soil Mechanics & Foundations Division from the Committee on Earths and Foundations, which had been established in 1929. The first Executive Committee of the new division was comprised of: W.P. Creager of Buffalo, Carlton S. Proctor of New York City, J. F. Coleman of New Orleans, Frank A. Marston of Boston, and R.V. Labarre of Los Angeles. Proctor served as the first Chairman and Theodore T. Knappen, formerly of the Corps of Engineers, was the first division secretary.
First Soil Mechanics & Foundations Division theme session at an ASCE meeting (1938)
"Practical Application of Soil Mechanics: A Symposium.” Presenters: Spencer J. Buchanan, Stanley M. Dore, B. K. Hough, Jr., and Karl Terzaghi. Discussions submitted by: George E. Beggs, M. L. Enger, R. J. Fogg, Harry T. Immerman, D. P. Krynine, F. A. Marston, George Paaswell, Ralph R. Proctor, Karl Terzaghi, Lazarus White, Glennon Gilboy, S. C. Hollister, Theodore T. Knappen, L. F. Harza, Edward A. Richardson, Richards M. Strohl, William P. Creager, Jacob Feld, Y. L. Chang, Charles Senour, Donald M. Burmister, Donald W. Taylor, Lee H. Johnson, Jr., Gregory P. Tschebotarioff, William L. Wells, A. Streiff, Spencer J. Buchanan, Stanley M. Dore, and B. K. Hough, Jr. Proctor was employed by the Los Angeles Department of Water & Power.
Geological Map of California (1938-onward)
In 1938 the State Division of Mines and Mining released their initial six-sheet Geologic Map of California (edited by Olaf P. Jenkins, Chief Mineralogist of the Division of Mines) at a scale of 1:500,000 (about an inch to 8 miles). The sheets took nine years to compile and showed about one-quarter of the state’s land are to be unmapped, including the Klamath Mountains, the northern Coast Ranges, the southern Sierra Nevada, and the desert areas of southeastern California. Much of this early work was carried out by field geology courses taught by Berkeley, Stanford, Caltech, and UCLA each summer. These maps were out-of-print by 1952. The first generation maps were superseded by more detailed Geologic Atlas of California at 1:250,000 scale (1 inch = 4 miles) geologic map sheets released by the California Division of Mines & Geology (after a name change in 1961), between 1958-66 (described below). DMG also released a 1:750,000 scale State Geology Map in 1977, which was reprinted in 1991 (small enough to be mounted on a classroom wall). More recent interpretations have subsequently been in release since 1982, and continue to the present. This series of maps covers all of California and is considered basic information that would be cited in any engineering geologic study.
US Forest Service maps (1937-45)
The USGS prepared 1:125,000 scale topographic maps of all the mountainous regions of southern California prior to 1945, under interagency contract with the US Forest Service. These include all of Santa Barbara, Ventura, Los Angeles, Orange, west San Bernardino, west Riverside, San Diego and Imperial Counties. Sometimes these maps are useful for age placement of roads and trails in these areas.
Government aerial mapping of California (1938-40)
Between 1938-40 the U.S. Soil Conservation Service (SCS) contracted for all of California to be photographed with black and white stereopair aerial images. Soils data for each county were usually plotted directly upon large prints of these photos (described in W.C. Lowdermilk’s article Use of Aerial Mapping in Soil Conservation, in Civil Engineering, v.8:9, September 1938, pp. 605-07). After 1945 soil designations were then represented spatially on black-and-white photo mosaics. These post-1940 SCS reports contain soils information of reliable accuracy.