Arch

The geometry of the arch section is actually very non-standard. It seems that there is not single equation governing the design of arch pipe. All manufactures tend to vary the specific dimensions of the various arch dimensions. To provide an approximate solution to arch shaped sections, the program relies on a set of table provided in Modern Sewer Design, American Iron and Steel Institute, 1995 for guidance.

Hydraulic Properties of Arch Conduits Flowing Part Full

Determination of Arch Area

Determination of Area
	Values of A/BD
Y/D	0	0.01	0.02	0.03	0.04	0.05	0.06	0.07	0.08	0.09
0.1		0.072	0.081	0.09	0.1	0.109	0.119	0.128	0.138	0.148
0.2	0.157	0.167	0.177	0.187	0.197	0.207	0.217	0.227	0.237	0.247
0.3	0.257	0.267	0.0277	0.287	0.297	0.307	0.316	0.326	0.336	0.346
0.4	0.365	0.356	0.375	0.385	0.394	0.404	0.413	0.423	0.432	0.442
0.5	0.451	0.46	0.47	0.479	0.488	0.497	0.506	0.515	0.524	0.533
0.6	0.541	0.55	0.559	0.567	0.576	0.584	0.592	0.6	0.608	0.616
0.7	0.624	0.632	0.64	0.647	0.655	0.662	0.67	0.677	0.684	0.69
0.8	0.697	0.704	0.71	0.716	0.722	0.728	0.734	0.74	0.745	0.75
0.9	0.755	0.76	0.764	0.769	0.772	0.776	0.78	0.783	0.785	0.787
1.0	0.788

Determination of Hydraulic Radius

Determination of Hydraulic Radius
	Values of R/D
Y/D	0	0.01	0.02	0.03	0.04	0.05	0.06	0.07	0.08	0.09
0.1		0.078	0.086	0.094	0.102	0.110	0.118	0.126	0.133	0.141
0.2	0.148	0.156	0.163	0.170	0.177	0.184	0.191	0.197	0.204	0.210
0.3	0.216	0.222	0.228	0.234	0.240	0.245	0.25	0.256	0.261	0.266
0.4	0.271	0.275	0.28	0.284	0.289	0.293	0.297	0.301	0.305	0.308
0.5	0.312	0.315	0.319	0.322	0.325	0.328	0.331	0.334	0.337	0.339
0.6	0.342	0.344	0.346	0.348	0.350	0.352	0.354	0.355	0.357	0.358
0.7	0.360	0.361	0.362	0.363	0.363	0.364	0.364	0.365	0.365	0.365
0.8	0.365	0.365	0.364	0.364	0.363	0.362	0.361	0.360	0.359	0.357
0.9	0.355	0.353	0.350	0.348	0.344	0.341	0.337	0.332	0.326	0.318
1.0	0.299

Determination of Arch Top Width

Determination of Top Width
	Values of T/B
Y/D	0	0.01	0.02	0.03	0.04	0.05	0.06	0.07	0.08	0.09
0.1		0.9	0.914	0.927	0.938	0.948	0.956	0.964	0.971	0.976
0.2	0.982	0.986	0.99	0.993	0.995	0.997	0.998	0.998	0.998	0.999
0.3	0.997	0.996	0.995	0.993	0.991	0.989	0.987	0.985	0.982	0.979
0.4	0.976	0.971	0.967	0.964	0.96	0.956	0.951	0.947	0.942	0.937
0.5	0.932	0.927	0.921	0.916	0.91	0.904	0.897	0.891	0.884	0.877
0.6	0.87	0.863	0.855	0.847	0.839	0.83	0.822	0.813	0.803	0.794
0.7	0.784	0.773	0.763	0.752	0.741	0.729	0.717	0.704	0.691	0.678
0.8	0.664	0.649	0.634	0.618	0.602	0.585	0.567	0.548	0.528	0.508
0.9	0.486	0.462	0.437	0.41	0.381	0.349	0.313	0.272	0.223	0.158