Dimensions and Weights: Elliptical Concrete Pipe

Dimensions and approximate weights of horizontal elliptical concrete pipe manufactured to ASTM C 507, reinforced concrete elliptical culvert, storm drain and sewer pipe. Elliptical sections exist to deliver the waterway area of a large circular pipe within materially less vertical rise, and the tables below are the numbers that make that trade explicit.

Equivalent round size is the entry point

Every row is indexed by equivalent round size — the diameter of the circular pipe whose waterway area the elliptical section matches. This is the column to enter with once the hydraulic design has produced a required area, and it is the single most misread quantity in the table. A 48 in. equivalent round elliptical section measures 60 in. across the major axis and 38 in. on the minor axis. It is wider than a 48 in. circular pipe and roughly ten inches shallower, and it carries approximately the same flow.

That ten inches is the entire reason the product exists. On a shallow crossing under a road with a fixed profile, or under an existing utility, ten inches of rise is frequently the difference between a workable design and a re-profiled road.

What the extra span costs

Nothing is free. Reading across the table, an elliptical section is heavier than the circular pipe of the same equivalent round size — 1,000 lb/ft at 48 in. equivalent round, against 867 lb/ft for Wall B circular pipe. It is also wider, which means a wider trench and closer attention to clearance either side. And the load distribution around a non-circular section differs from a circular one, which is why Table IIB uses its own HE and A class notation rather than the Roman numeral classes.

English units

Horizontal elliptical concrete pipe, ASTM C 507 — dimensions and approximate weights (English units)
Equivalent round size, in	Minor axis, in	Major axis, in	Min. wall thickness, in	Waterway area, sq ft	Approximate weight, lb/ft
18	14	23	2.75	1.8	195
24	19	30	3.25	3.3	300
27	22	34	3.50	4.1	365
30	24	38	3.75	5.1	430
33	27	42	3.75	6.3	475
36	29	45	4.50	7.4	625
42	34	53	5	10.2	815
48	38	60	5.50	12.9	1000
54	43	68	6	16.6	1235
60	48	76	6.50	20.5	1475
66	53	83	7	24.8	1745
72	58	91	7.50	29.5	2040
78	63	98	8	34.6	2350
84	68	106	8.50	40.1	2680
90	72	113	9	46.1	3050
96	77	121	9.50	52.4	3420
102	82	128	9.75	59.2	3725
108	87	136	10	66.4	4050
114	92	143	10.50	74.0	4470
120	97	151	11	82.0	4930
132	106	166	12	99.2	5900
144	116	180	13	118.6	7000

Metric units

Horizontal elliptical concrete pipe, ASTM C 507 — dimensions and approximate masses (metric units)
Equivalent Round Size, inches	Equivalent Round Size, mm	Minor Axis, mm	Major Axis, mm	Minimum Wall Thickness, mm	Waterway Area, square meters	Approximate Weight, kg., per meter
18	450	356	584	70	0.17	290
24	600	483	762	83	0.31	445
27	686	559	864	89	0.38	545
30	750	610	965	95	0.47	640
33	825	686	1067	95	0.58	705
36	900	737	1143	114	0.69	930
42	1050	864	1346	127	0.95	1215
48	1200	965	1524	140	1.20	1490
54	1350	1092	1727	152	1.54	1840
60	1500	1219	1930	165	1.90	2195
66	1676	1346	2108	178	2.30	2595
72	1800	1473	2311	190	2.74	3035
78	1950	1600	2489	203	3.21	3495
84	2100	1727	2692	216	3.73	3990
90	2250	1829	2870	229	4.28	4540
96	2400	1956	3073	241	4.87	5090
102	2550	2083	3251	248	5.50	5545
108	2700	2210	3454	254	6.17	6025
114	2850	2337	3632	267	6.87	6650
120	3000	2464	3835	279	7.62	7335
132	3350	2692	4216	305	9.22	8780
144	3650	2946	4572	330	11.02	10415

Reading the axes

The major axis is the long dimension and the minor axis the short one. Horizontal elliptical pipe is installed with the major axis horizontal, so the major axis is the span and the minor axis is the rise. ASTM C 507 also defines vertical elliptical classes, installed with the major axis vertical, for the opposite constraint — a narrow trench or a deep installation where horizontal room rather than height is scarce. Orientation must be stated on the drawings. A section installed on the wrong axis is not merely misaligned; it is in a loading condition it was not designed for.

Minimum wall thickness rises with equivalent round size from 2.75 in. at the smallest section to 13 in. at 144 in. equivalent round. As with circular pipe, weights are approximate and given for estimating, handling and transport; the producer's schedule governs for an order.

Arch pipe as an alternative

Arch pipe under ASTM C 506 solves the same clearance problem with different geometry, generally shallower in rise and wider in span than an elliptical section at the same equivalent round size. Both are tabulated side by side in Table IIB, and where one shape is not produced regionally the other substitutes at the same equivalent round size. Confirm availability with local producers before fixing the design; current dimensional data is maintained by the American Concrete Pipe Association.